ANACAPA ISLAND RESTORATION PROJECT Final EIS Full.pdf · on the island. Actions to ensure that a...

A N AC A PA I S L A N DR E S T O R AT I O N P RO J E C T

FINAL ENVIRONMENTAL IMPACT STATEMENT

National Park Service

Channel Islands National ParkVentura County, California

October, 2000

C H A N N E L I S L A N D S N A T I O N A L P A R K F I N A L E N V I R O N M E N T A L I M P A C T S T A T E M E N T

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ABSTRACT - I

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A N AC A PA I S L A N D R E S T O R AT I O NP RO J E C T

FINAL ENVIRONMENTAL IMPACT STATEMENTChannel Islands National Park

Ventura County, California

October, 2000

Responsible OfficialJohn Reynolds, Regional Director

Pacific West Region600 Harrison Street, Suite 600

San Francisco, CA 94107-1372

Lead Agency:USDI National Park Service

For Further InformationTim Setnicka, SuperintendentChannel Islands National Park

1901 Spinnaker Dr.Ventura, CA 93001

Abstract


This Final Environmental Impact Statement (FEIS) was prepared in accordance with the Department of the Interior NationalEnvironmental Policy Act (NEPA) regulations, and the National Park Service NEPA guidelines (NPS-12). As required byNEPA, this FEIS is necessary because actions proposed as part of this FEIS are considered a major federal action significantlyaffecting the quality of the human environment.

Channel Islands National Park in coordination with the Island Conservation and Ecology Group formulated the proposed action tomitigate the ecological degradation that is occurring on Anacapa Island from the impacts of the non-native Black Rat. The purpose ofthe proposed action is to eradicate rats from Anacapa Island and keep it and Santa Barbara Island, Prince Island and Sutil Island rat-free. Maintaining rat-free islands would improve seabird-nesting habitat and would aid in the recovery of crevice nesting seabirds suchas the Xantus’ Murrelet and Ashy Storm-Petrel.

The proposed action involves the aerial and hand placed ground application of a bait containing the rodenticide brodifacoum intoall rat territories on Anacapa Island. Application of the rodenticide would occur during the fall of the year to minimize disturbance andexposure to other affected resources on the island. The Park conducted extensive “scoping” on the proposed action. As a result ofcomments from interested public, federal and state agencies, and conservation groups on the proposed action, the Park identified threesignificant environmental issues. The significant environmental issues are: 1) Efficacy on target species; 2) Impacts on non-targetspecies; and 3) Impacts to the public and visitor use.

To address these significant environmental issues, the Park prepared five alternatives to the proposed action. Each alternative wasdeveloped to respond to the environmental issues identified. The Park also considered many other alternatives and methods toeradicate the Black Rat on Anacapa Island; however, many of the methods failed to meet the purpose and need of the project.

As part of this FEIS the Park described the “Affected” environment for the project. This section describes what is currentlyknown about the status and the trend of affected island resources. The affected environment included the physical setting of the island,terrestrial resources, and marine resources.

For full disclosure, the Park prepared an analysis of the environmental consequences that would occur should any of thealternatives presented be chosen for implementation.

No sooner than 30 (thirty) days after release of this FEIS a Record of Decision (ROD) will be executed. Release of the FEIS isexpected on or around October 13, 2000. John Reynolds, Regional Director, Pacific West Region, is responsible for the final decision.Tim Setnicka, Superintendent, Channel Islands National Park, is responsible for plan implementation and monitoring of all activities.

GLOSSARY- II

Glossary of Terms and Abbreviations

AIRP Anacapa Island Restoration Project

ATTC American Trader Trustee Council

EC50 Effective Concentration. The concentration at which 50% of an exposed testpopulation is affected sublethally.

EIS Environmental Impact Statement

EPA Environmental Protection Agency

ERP Emergency Response Plan

ESA Endangered Species Act

ft Foot. 1 ft = 30 centimeters or 12 inches

g Gram. 1 g = 0.035 oz.

GMP NPS General Management Plan

GPS Global Positioning System

ha Hectare. 1 ha = 2.47 acres

ICEG Island Conservation and Ecology Group

kg Kilogram. 1 kg = 2.205 pounds

LC50 LC - Lethal Concentration. Concentration of active ingredient that couldcause death in 50% of an animal test population. Presented as mg activeingredient per unit volume.


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ANACAPA ISLAND RESTORATION PROJECTFINAL ENVIRONMENTAL IMPACT STATEMENT

GLOSSARY- III

LD50LD – Lethal Dose. Acute oral dose required to cause death in 50% of ananimal test population. Presented as mg active ingredient per kg bodyweight (mg/kg).

LOC Level of Concern. See text.

mg Milligram. 1/1000 of a gram.

NEPA National Environmental Policy Act

NPS National Park Service

ppm Parts per million

PT Prothrombin time. A measure of blood clotting time.

RMP NPS - Resources management plan

RQ Risk Quotient = Exposure/Toxicity. See text.

USFWS US Fish and Wildlife Service

SUMMARY - IV

ANACAPA ISLANDRESTORATION PROJECT

SUMMARY OF THE FINAL ENVIRONMENTALIMPACT STATEMENT

Introduction

This Final Environmental Impact Statement analyzes the effects of implementing

proposed actions that accomplish the following objectives: 1) eradication of the

introduced Black Rat on Anacapa Island; 2) adopt an emergency response plan for

accidental introductions of rodents on Anacapa, Santa Barbara, Prince, and Sutil Islands;

and 3) incorporate a prevention strategy to reduce the potential for rodents to be

accidentally introduced to Park islands. The proposed action was developed in concert

with the Island Conservation and Ecology Group and is based on other successful island

rat eradication efforts worldwide. Actions to manage existing and potential Black Rat

infestations is necessary because of the ecological impacts Black Rats are having on

Anacapa Island, and the potential negative impact they would have if introduced to other

Park islands.

Public Involvement

In compliance with the National Park Service National Environmental Policy Act

(NEPA) implementing regulations, the Park conducted “scoping” on the proposed action.

Scoping involved contacting interested publics, regulatory agencies with oversight

concerns, conservation groups, and worldwide experts in the field of vertebrate pest

ecology. The Park used several methods to solicit comment on the proposed action


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ANACAP A ISLAND RES TOR AT ION PRO JEC T

FIN AL ENV IRON MEN T AL IMP ACT ST AT E MEN T

SUMMARY - V

including letters, public meetings, web-site, press releases, and press, radio and television

advertisements.

Environmental Issues

Based on internal and external comments on the proposed action the Park concluded

that the analysis would need to address three significant environmental issues. These

issues are: 1) Efficacy on Target species; 2) Impacts to Non-target species; and 3) Effect

on public use and visitation.

Issue Description

TargetSpeciesEfficacy

Efficacy for this analysis is defined as how well the alternative would meet the100% eradication objective.

Non-TargetSpecies:

Impacts to non-target species are separated into two categories: physical disturbanceand toxicological risk. Physical disturbance may occur from the activitiesassociated from baiting, and monitoring. Toxicological risk will analyze bothprimary (direct) exposure and secondary (indirect) exposure.

PublicUse/Visitation

Anacapa Island is the most visited of all the islands in the Park. Although campingis allowed on East Anacapa, day trips via the concessionaire boats is the mostcommon visitation that occurs on the island.

The issue “Impacts to Non-target species” is a broad category that incorporates

several sub-issues. The sub-issues are the species groups that may be impacted by the

proposed action. The following taxonomic hierarchy identified the species groups that

may be impacted by the project:

Non-Target Impacts

MammalsSub-Issue 1

InvertebratesSub-Issue 2

FishesSub-Issue 3

Marine

Flora

InvertebratesSub-Issue 2

HerpetofaunaSub-Issue 4

SeabirdsSub-Issue 5

LandbirdsSub-Issue 6

Avian MammalsSub-Issue 7

Fauna

Terrestrial

Sub-Issue 8



SUMMARY - VI

AlternativesAfter identifying the significant environmental issues associated with the proposed

action, the Park began developing alternatives by modifying the eradication strategies to

address the environmental issue concerns. In all, six alternatives were developed,

including the “No Action” alternative.

Several methods and techniques were rejected from consideration. Exclusive use of

bait stations (elevated and ground) was rejected because of the steep cliffsides on

Anacapa Island and the problems associated with placing bait stations in all of the rat

territories on the island, including the steep cliffsides. Studies cited in the analysis

documented that not all rats could access the elevated bait stations. Several alternate

rodenticides were also considered, but were rejected because: 1) they had not been used

previously in successful island eradication; 2) they had potential to cause bait shyness; 3)

they could not cope with the potential “Warfarin resistant” rats; and 4) there is no

Summary of Alternatives.

East Anacapa Middle Anacapa West AnacapaAlternative

Top Cliff Top Cliff Top CliffActive

IngredientConcentration

(ppm)

1 (No Action) NA NA NA NA NA NA NA NA

2 (Preferred) Aerial/Hand

Aerial/Hand

Aerial/Hand

Aerial/Hand

Aerial/Hand

Aerial/Hand Brodifacoum 25

3 BaitStn Aerial Bait

Stn Aerial Aerial Aerial Brodifacoum 25

4 Aerial Aerial Aerial Aerial Aerial Aerial Bromadiolone 50


Stn Aerial Aerial Aerial Bromadiolone 50

6 Aerial Aerial Aerial Aerial Aerial AerialDiphacinone

andBrodifacoum

50and25



SUMMARY - VII

antidote for some of the rodenticides. Exclusive use of trapping, and introduction of

predators were both rejected because they failed to meet the purpose and need.

Environmental Consequences

For each environmental issue, the Park analyzed the potential effects that may occur

should one of the six alternatives be implemented. For Issue 1 (Efficacy), analysis

focused on the probability of a successful eradication for each alternative. Factors

considered in the analysis included the toxicology of the rodenticide, bait composition

and delivery into the ecosystem, and local factors. From an efficacy standpoint,

Alternative Two (preferred action) offers the highest probability of success in eradicating

rats from the island.

For Issue 2 (Non-Target Impacts), each alternative was analyzed for potential

physical disturbance, as well as the toxicological effects of the proposed rodenticide on

non-target species. The physical impacts were restricted to short-term disturbance to

landbird, seabird, and marine mammal species.

Toxicological impacts were analyzed for a wide range of species that may be present

in the project area. The effects analysis included both primary exposure (direct

consumption of the bait containing the rodenticide), and secondary exposure (species

who feed on animals that have been directly exposed) impacts. Mitigation measures

were incorporated for species at risk of exposure. The presence of the endemic deer

mouse on Anacapa Island presented a logistical challenge because they are at risk of

exposure to the rodenticide, but must be protected to ensure a viable population remains

on the island. Actions to ensure that a viable population of the endemic Anacapa deer

mouse remain on the island are incorporated into each action alternative.

For Issue 3 (Public Use and Visitation), each alternative was analyzed for its potential

to expose island visitors to rodenticides, and the potential impacts to visitor enjoyment

and visitation. Rodenticide exposure to the public, although considered to be a very low

risk was analyzed in detail to quantify the potential risk. Mitigation measures are

presented to minimize this risk further. In addition, the use of bait stations (as opposed



SUMMARY - VIII

to broadcast spreading of bait) around public areas was built into all of the action

alternatives. Rodenticide bait will not be used inside structures. The structures on east

islet were rodent proofed in 1999, snap traps will be used to determine if rodents are

getting into the buildings. Indoor snap trapping would begin prior to island-wide baiting

operations. The 2-3 day restriction around the application period would preclude island

visitation to East Anacapa during the slowest part of the visitation year.

TABLE OF CONTENTS - IX


TABLE OF CONTENTS

ABSTRACT......................................................................................................................... I

GLOSSARY........................................................................................................................II

SUMMARY OF FEIS....................................................................................................... IV

Chapter One – Purpose and NeedINTRODUCTION ............................................................................................................... 2GENERAL MANAGEMENT PLAN DIRECTION............................................................... 2PROPOSED ACTION AND PURPOSE & NEED ............................................................. 3

Purpose .......................................................................................................................... 3Need For Action ............................................................................................................ 3

Introduced Species and Island Ecosystems ........................................................................ 3Introduced Commensal Rats............................................................................................... 4Impacts of Introduced Rats on Island Ecosystems.............................................................. 5Rats on Anacapa Island ...................................................................................................... 5

Proposed Action ............................................................................................................ 6Anacapa Rat Eradication ................................................................................................... 6Emergency Response Plan.................................................................................................. 7Prevention........................................................................................................................... 7

SCOPE OF THE PROPOSED ACTION............................................................................. 8DECISIONS TO BE MADE................................................................................................. 8

Chapter Two - AlternativesINTRODUCTION ............................................................................................................ 11ALTERNATIVE DEVELOPMENT PROCESS ............................................................. 11

INTERNAL SCOPING AND PUBLIC INVOLVEMENT.................................................................... 11Significant Environmental Issues ..................................................................................... 12Issue 1: Efficacy on Target Population ........................................................................... 12Issue 2: Impact to Non-Target Species ............................................................................. 12

Sub-issue 1 - Marine Mammals ............................................................................................................... 13Sub-Issue 2 - Invertebrates (Marine/Terrestrial)...................................................................................... 13Sub-Issue 3 - Marine Fishes .................................................................................................................... 14Sub-Issue 4 - Herpetofauna ..................................................................................................................... 14


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ANACA PA ISLAND RES T ORAT ION PRO JECT

FINAL ENVIRON MENTAL IM PA CT ST AT EM EN T

TABLE OF CONTENTS - X

Sub-Issue 5 - Seabirds ............................................................................................................................. 14Sub-Issue 6 - Landbirds........................................................................................................................... 14Sub-Issue 7 - Mammals (Terrestrial) ....................................................................................................... 15Sub-Issue 8 - Flora...................................................................................................................................15

Issue 3: Public Safety and Visitation .......................................................................... 15

Issues Dismissed from Analysis................................................................................... 15

ALTERNATIVES CONSIDERED IN DETAIL.............................................................. 16INTRODUCTION........................................................................................................................ 16FEATURES COMMON TO ALL ACTION ALTERNATIVES ........................................................... 16

Effectiveness and Validation Monitoring ................................................................................................ 16Non-native Rodent Introduction Prevention Plan .................................................................................... 17Protection of Native Deer Mouse Population .......................................................................................... 17Rat Detection Response Plan................................................................................................................... 18Human Health ........................................................................................................................................................ 18Timing ..................................................................................................................................................... 18Permits and Approval .............................................................................................................................. 18Public Awareness .................................................................................................................................... 18Visitation Restrictions ............................................................................................................................. 18

ALTERNATIVES .................................................................................................................... 19ALTERNATIVE ONE - No Action ................................................................................................................ 19ALTERNATIVE TWO (Proposed Action and Preferred Alternative) – Aerial broadcast of a Rodent BaitContaining Brodifacoum ................................................................................................................................. 19ALTERNATIVE THREE - Bait Stations for Top of Island and AerialBroadcast the Cliffsides with Brodifacoum..................................................................................................... 20ALTERNATIVE FOUR - Aerial broadcast of a Rodent Bait Containing Bromadiolone ............................... 22ALTERNATIVE FIVE - Bait Stations for Top of Island and AerialBroadcast the Cliffsides with Bromadiolone ................................................................................................... 23ALTERNATIVE SIX - Aerial broadcast of a Rodent Bait ContainingDiphacinone followed by a Rodent Bait Containing Brodifacoum.................................................................. 24

ALTERNATIVES CONSIDERED AND REJECTED .................................................... 26BAIT STATIONS........................................................................................................................ 26ELEVATED BAIT STATIONS ..................................................................................................... 26ALTERNATE RODENTICIDES .................................................................................................... 26TRAPPING ................................................................................................................................ 28INTRODUCING PREDATORS...................................................................................................... 29

SUMMARY OF ALTERNATIVES ..................................................................................... 29

Chapter Three – Affected EnvironmentINTRODUCTION............................................................................................................. 32

PHYSICAL ENVIRONMENT......................................................................................... 32SETTING................................................................................................................................... 32GEOLOGY ................................................................................................................................ 32SOILS ....................................................................................................................................... 34CLIMATE.................................................................................................................................. 34AIR QUALITY (CLEAN AIR ACT) ........................................................................................... 35

TERRESTRIAL ENVIRONMENT.................................................................................. 36



TABLE OF CONTENTS - XI

INVERTEBRATES ...................................................................................................................... 36HERPETOFAUNA ...................................................................................................................... 37AVIAN...................................................................................................................................... 38

Landbirds.......................................................................................................................... 38Seabirds ............................................................................................................................ 38

Brown Pelican (Endangered) .................................................................................................................. 39Species of Special Concern ..................................................................................................................... 40

MAMMALS............................................................................................................................... 41RARE, THREATENED AND ENDANGERED PLANTS................................................................... 41

MARINE ENVIRONMENT............................................................................................. 42MARINE MAMMALS................................................................................................................. 42

California Sea Lion........................................................................................................... 42Harbor Seal ...................................................................................................................... 42

MARINE INVERTEBRATES........................................................................................................ 44HUMAN USES AND VALUES......................................................................................... .45

Chapter Four – Environmental Consequences

INTRODUCTION............................................................................................................. 48

ISSUE 1: EFFICACY ...................................................................................................... 48INTRODUCTION........................................................................................................................ 48THE RODENTICIDE AND TOXICOLOGICAL PROPERTIES.......................................................... .48COMPOSITION OF BAIT AND HOW IT IS APPLIED ..................................................................... 50

Alternative 1- No Action Alternative ................................................................................ 50Alternatives 3 & 5: Aerial - Bait Station Combined........................................................ 50Alternatives 2, 4 and 6: Aerial Broadcast ....................................................................... 51

ISSUE 2: NON-TARGET IMPACTS.............................................................................. 52INTRODUCTION........................................................................................................................ 52PHYSICAL IMPACTS ................................................................................................................. 52TOXICOLOGICAL IMPACTS....................................................................................................... 57

Introduction ...................................................................................................................... 57Biochemistry............................................................................................................................................ 57

Relative Comparison of Toxicological Impacts by Alternative ........................................ 58Primary Exposure .................................................................................................................................... 58Secondary Exposure ................................................................................................................................ 61

Toxicological Impacts by Sub-Issue ................................................................................. 64Sub-Issue 1: Marine Mammals ............................................................................................................... 64Sub-Issue 2: Invertebrates....................................................................................................................... 66Sub-Issue 3: Marine Fishes..................................................................................................................... 66Sub-Issue 4: Herpetofauna...................................................................................................................... 67Sub-Issue 5 & 6: Seabirds and Landbirds............................................................................................... 69

Sub-Issue 7: Terrestrial Mammals .......................................................................................................... 74CUMULATIVE EFFECTS............................................................................................................ 74

ISSUE 3: PUBLIC SAFETY AND VISITATION........................................................... 78 Exposure to the rodenticide ............................................................................................................................ 78

Impacts to Visitor Enjoyment......................................................................................................................... 80



TABLE OF CONTENTS - XII

SUSTAINABILITY AND LONG TERM MANAGEMENT .......................................... 81

Chapter Five – Coordination and Consultation

COORDINATION ............................................................................................................ 84

PUBLIC INVOLVEMENT............................................................................................... 84INTERNAL SCOPING ................................................................................................................. 84EXTERNAL SCOPING................................................................................................................ 84

LIST OF PREPARERS..................................................................................................... 85

LIST OF RECIPIENTS..................................................................................................... 86

RESPONSE TO COMMENTS......................................................................................... 87

References ................................................................................................... 108

Index ............................................................................................................ 119

APPENDIX A ................................................................................................................. 121

APPENDIX B ................................................................................................................. 127

APPENDIX C ................................................................................................................. 137

APPENDIX D ................................................................................................................. 139


CHAPTER ONE - 1

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A N A C A PA I S L A N D R E S T O R A T I O NP R O J E C T

Chapter one

CHAPTER ONEPURPOSE AND NEED

Need

Chapter Contents

INTRODUCTION .......................................................................................................................... 2

GENERAL MANAGEMENT PLAN DIRECTION........................................................................... 2

PROPOSED ACTION AND PURPOSE & NEED ......................................................................... 3

Purpose ...................................................................................................................................... 3

Need For Action ........................................................................................................................ 3Introduced Species and Island Ecosystems ......................................................................................3Introduced Commensal Rats ............................................................................................................4Impacts of Introduced Rats on Island Ecosystems ...........................................................................5Rats on Anacapa Island....................................................................................................................5

Proposed Action ........................................................................................................................ 6Anacapa Rat Eradication ................................................................................................................6Emergency Response Plan ...............................................................................................................7Prevention ........................................................................................................................................7

SCOPE OF THE PROPOSED ACTION......................................................................................... 8

DECISIONS TO BE MADE............................................................................................................. 8


CHAPTER ONE - 2

IntroductionChannel Islands National Park has prepared

this Final Environmental Impact Statement todocument environmental impacts that would beassociated with eradication, prevention, andemergency response management actionsassociated with non-native rat (Rattus) species.Specifically, this FEIS will cover proposedmanagement actions in the following three areas:1) Eradication of the Black Rat (Rattus rattus) onAnacapa Island; 2) An emergency response planfor dealing with accidental introductions of ratson Anacapa, Santa Barbara, Prince, and SutilIslands; and 3) A prevention strategy to reducethe potential for rats to be accidentally introducedto Park islands. This FEIS includes analysis ofeffects for six alternatives, including theconsequences of not eradicating the Black Ratsfrom the Island, or not reacting to or preventingrat introductions to Park islands.

This Final EIS is based on direction containedin the National Environmental Policy Act(NEPA), Council on Environmental Quality(CEQ) regulations 40 CFR 1500-1508, and theNational Park Service NEPA implementationguideline (NPS-12).

The Final EIS will also document the Park’sobligation to meet other federal laws including:The National Historic Preservation Act; FederalWater Pollution Control Act (Clean Water Act);Clean Air Act; Coastal Zone Management Act;Marine Mammal Protection Act; and theEndangered Species Act.

CEQ regulations require a Notice ofAvailability (NOA) be made to the FederalRegister that a final EIS has been completed. ThePark will wait at least 30 days from the FederalRegisters publishing of the NOA before signing arecord of decision.

Channel Islands National Park GeneralManagement Plan (GMP) provides direction formanagement of the Park. Decisions and directionidentified in these documents are incorporated byreference. This EIS is “tiered” to the GMP aspermitted by 40 CFR 1502.2.

General Management PlanDirection

The General Management Plan (GMP)completed in 1985 defines management directionfor the natural resources within the Park. In thisGMP specific objectives are stated for Anacapa,San Miguel, and Santa Barbara Islands.Objectives from the GMP which support theAnacapa Island Restoration Project include:� Restore altered ecosystems as nearly as

possible to conditions they would be in todayhad natural ecological processes not beendisturbed.

� Develop an awareness of threats that impactor have the potential to impact Park resources.

� Actively respond, as a land managementagency, to these potential threats.

In addition to stating general managementobjectives, the plan identifies specific objectivesfor island resources. Management guidelines tomeet objectives were also described in the Plan.Black Rats are specifically mentioned in theGMP. The objective stated for Black Ratmanagement is “eradication”. The action to meetthis objective calls for the Park to initiate aneradication program on East Anacapa Island.Under the criteria established by the GMP for rateradication, such a program must:

a) Be effective

b) Be selective for rats

c) Have the least possible effect on native mousepopulations and other forms of plant andanimal life


CHAPTER ONE - 3

d) Present the lowest risk to visitors and staff

e) Be economical and simple to maintain

Alternatives proposed in this analysis meetthese criteria to varying degrees.

The Resources Management Plan (RMP) alsoidentifies this project as a necessary action toperpetuate natural processes and resources withinthe Park. The RMP flows from the GeneralManagement Plan (1985) and Statement forManagement (1991). The RMP is the Park’sstrategic plan for the long-range management ofits resources and a tactical plan identifying short-term projects.

Purpose & Need andProposed Action

PurposeThe purpose of the proposed action is to

eradicate rats from Anacapa Island and keep it andall Park islands rat-free. Eradicating rats fromAnacapa Island would improve seabird-nestinghabitat and could aid in the recovery of somespecies such as the Xantus’ Murrelet and AshyStorm-Petrel.

Need for Action

Introduced Species and theImportance of Island Ecosystems

It is now widely accepted that current ratesof species extinctions are dramatically higherthan background rates (Raup 1988), that mostcurrent extinctions can be directly attributed tohuman activity (Diamond 1989), and that forethical, cultural, aesthetic, and economicreasons, this current rate of extinction is causefor considerable concern (Ehrlich 1988, Ledecand Goodland 1988). The causes of

anthropogenic extinctions can be roughlydivided into four broad categories: non-sustainable use of resources, habitat destruction,pollution, and introduction of non-nativespecies.

Problems in the first three categories areoften acute and can directly affect humanwelfare on an observable time scale. Thesequalities have made them the focus of publicenvironmental concern. The introduction ofnon-native species has received less publicityand professional attention (Coblentz 1990,Soulé 1990); however, introduced species areresponsible for 39% of all recorded animalextinctions since 1600 for which a cause couldbe attributed (World Conservation MonitoringCentre 1992). Thus, some impacts ofintroduced species are irreversible (reviewedby Groves and Burdon 1986; Mooney andDrake 1986; and Hengeveld 1989) and at leastas devastating as the other categories(Atkinson 1985, 1989, Soulé 1990). Onceestablished, introduced species often becomepermanent in ecological time unlessintentionally removed (Tershy and Croll 1994).

Island ecosystems are particularlyvulnerable to both extinctions and the impactsof introduced species (Diamond 1985, 1989,Olson 1989). Of the 484 recorded animalextinctions since 1600, 75% have been islandendemics (World Conservation MonitoringCentre 1992). Introduced species werecompletely or partially responsible for 67%these extinctions (based on the 147 islandspecies for which the cause of extinction isknown, calculated from World ConservationMonitoring Centre 1992).

Islands are important to the conservation ofbiodiversity for four reasons:

1) A large percentage of their biota areendemic species and subspecies (Darwin1859, Elton 1958);


CHAPTER ONE - 4

2) They are important breeding areas forseabirds, pinnipeds, and sea turtles,which forage over thousands of square

kilometers of ocean but are dependent onrelatively small amounts of protectedland on islands for breeding and nesting;

3) Many islands are sparsely inhabited oruninhabited by humans, keepingsocioeconomic costs of protection low;

4) the species and ecological communitieson islands have evolved in naturalfragments, making them less susceptiblethan continental species to the problemsof habitat fragmentation caused by smallreserve size.

In summary, by restoring and protectingislands, functioning unmanaged ecosystems canbe maintained without large expenditures forland acquisition or significant conflict with localhuman populations (Tershy and Croll 1994).

Introduced Commensal RatsThere are three species of rats in the genus

Rattus which are commensal with humans andwhich have been introduced to islandsthroughout the world. In order of decreasingsize they are: the Norway or Brown Rat (R.norvegicus), the ship or Black Rat (R. rattus),and the Pacific or Polynesian Rat (R. exulans).They have different dietary preferences,distributions and histories of introduction, but allthree species are omnivorous, behaviorallyplastic, have high reproductive rates, and cansurvive in a variety of habitats (Atkinson 1985,Moors et al. 1992). These traits make themideally suited to survive on a variety of predatorfree islands. At least one of the three speciesoccurs on an estimated 82% of all island groups,with R. rattus being the most commonintroduced rat (Atkinson 1985).

Figure 1: Location Map of Anacapa Island.


CHAPTER ONE - 5

Impacts of Introduced Rats on IslandEcosystems

The most obvious impacts of introduced ratson island ecosystems are extinctions of endemicspecies. Introduced rats (Rattus spp) areresponsible for an estimated 40 - 60% of all birdand reptile extinctions (ICEG Analysis of WorldConservation Monitoring Centre Data, Atkinson1985). They have caused extinctions of endemicmammals and invertebrates on the Galapagosand elsewhere (Andrews 1909, Brosset 1963,Daniel & Williams 1984, Meads et al. 1984).

Even if extinctions do not occur, rats can haveecosystem wide effects on the distribution andabundance of native species through direct andindirect effects. For example, comparisons of rat-infested and rat-free islands, or pre and post rateradication experiments, have shown that ratsdepressed the population size and recruitment ofbirds (Thibault 1995, Cambell 1991), reptiles(Whitaker 1973, Towns 1991, Cree et al. 1992),plants and terrestrial invertebrates. Rats have alsobeen shown to affect the abundance and agestructure of intertidal invertebrates (Navarrete &Castilla 1993).

Each of the three species of commensalRattus have been implicated in extinctions andprey populations changes. Due to their differentnatural histories, however, each species hasslightly different impacts. For example R.norvegicus tends to have a greater impact onadult burrow nesting seabirds than does R. rattus,but less of an impact on tree nesting birds(Atkinson 1985). Consequently, the introductionof new Rattus species should be avoided, even toislands which already have introduced rats (Moorset al. 1992).

Rats on Anacapa IslandsThe three Anacapa islets have been

subjected to introduced cats, sheep, rabbits, andrats. All but the rats have been successfully

eradicated. The Black Rat was introduced to theAnacapa Islands prior to 1939 (Sumner & Bond1939) probably in supplies transported onto theisland for sheep ranching or lighthouseconstruction, or from a ship wreck (Collins1980). Research on the Anacapa Island by Mainet al. (1972), Collins (1979), Erickson &Halvorson (1990), and Howald et al. (1997)demonstrate that Black Rats:

1) Are most abundant in the coastal areas andcanyons on the islands;

2) Breed from April through September;

3) Feed on native mammals, reptiles, insects,intertidal invertebrates, birds, and plants.

It is believed that the most significantimpact rats have on Anacapa Island is on thebreeding populations and breeding success ofthe colonial nesting seabirds, the Xantus’Murrelet (Synthliboramphus hypoleucus) andAshy Storm-Petrel (Oceanodroma homochra).These two species are California Species ofSpecial Concern(http://www.dfg.ca.gov/endangered/birds.html )and a federal (USFWS) Species of Concern(http://www.fws.gov/r9mbmo/reports/speccon/tblconts.html). Species of concern are a “highpriority for additional research and conservationactions,…”(http://www.fws.gov/r9mbmo/reports/speccon/mgmtrec.html). The California Channel Islandshost large proportions of the world populationsof these rare species.

Predatory mammals such as rats and catshave been identified by McChesney and Tershy(1998) as the main cause of long-term decline inXantus’ Murrelet populations. The relativelysmall size of the adults and crevice nestingbehavior makes them susceptible to predation byrats. Introduced rats prey on adults, chicks andeggs of many seabirds. Recent surveys ofAnacapa Island have found abundant evidenceof rat use of cliffs which coincides withpreferred murrelet nesting habitat (G.


CHAPTER ONE - 6

McChesney, pers. comm., Erickson andHalvorson 1990). Evidence of recent nestingactivity by murrelets was found at only 0.4% ofpotential nesting sites investigated on AnacapaIsland (as compared to a 30% success rate onSanta Barbara Island, and with no introducedrats), and all eggs found showed evidence ofmammalian predation (G. McChesney, unpub.data). Murrelets utilizing Anacapa are largelyrestricted to areas inaccessible to rats, such assea caves, although abundant nesting habitat isfound elsewhere. The removal of rats fromAnacapa Island will provide a substantialincrease in nesting habitat available to thesespecies in California. Seabird colonial nestinglikely has evolved in part from predationpressure (See McChesney and Tershy 1998), andAnacapa Island is only one of two of theCalifornia Channel Islands which historicallyhas provided terrestrial predator free breedinghabitat to seabirds. The other predator freeisland, Santa Barbara Island, currently supportsa large colony of Xantus’ Murrelets. Only smallnumbers of Xantus’ Murrelets breed at the otherChannel Islands. The abundance of nestinghabitat at Anacapa Island for crevice nestingseabirds such as Xantus’ Murrelet and AshyStorm-Petrel, coupled with Anacapa’s similarityto nearby Santa Barbara Island, suggest apotential for Anacapa to support largepopulations of these species (G. McChesney,pers. comm.). The restoration of AnacapaIsland to an introduced predator free status likelywill provide substantial benefits to these species.The removal of introduced rats from islands hasbeen identified as a priority to ensure therecovery and long-term viability of Xantus’Murrelet populations (McChesney and Tershy1998).

Proposed ActionAnacapa Rat Eradication

The technique proposed for eradicating ratson Anacapa Island is modeled after other islandrat eradication projects that have successfullybeen completed worldwide. Due to the steepcliffs of the island, an aerial broadcast isnecessary to deliver rodenticide to every rat’sterritory, a condition that has to be met toaccomplish eradication. The formation of theislands through uplifting has made the cliffsidesof Anacapa Island extremely unstable anddangerous to climb, and thus bait stations cannotbe safely placed and maintained on thecliffsides. The cliffsides harbor the greatestdensity of rats and so for eradication to beaccomplished adequate delivery of bait tocliffsides must be ensured. The placement ofrodenticide into every rat’s territory is critical tothe success of the eradication and cliffsides needto be treated. Therefore, broadcast application(aerial and hand broadcast) would be thepreferred method. Broadcast of the rodenticidebait would be carried out in all habitats acrossthe island. The rat population size on Anacapafluctuates between about 750 – 2,000, dependingon local conditions. Application of rodenticidewould be completed within 1-2 days.

A local certified agricultural pesticideapplicator would be used for conducting theapplication. The applicator would have to meetthe following criteria: 1) OAS and CaliforniaDepartment of Agriculture certification for aerialapplication of rodenticide; 2) Helicoptersequipped with differential GPS units to ensureeven coverage across the island; 3) Experiencein aerial activities in remote offshore ChannelIslands National Park.

Bait would be broadcast at a maximum rateof 15 kg of 25 ppm bait/ha. A maximum of twoapplications is anticipated.


CHAPTER ONE - 7

The chronology of eradication would beginwith baiting in representative habitat within theproject area. Representative habitat may includeall of East Islet or smaller area on Middle Isletthat allows for easy and unobtrusive access.Representative habitat contains prime rat habitatincluding intertidal areas, and dense vegetationsites. The objective of the initial eradicationtreatment is to conduct both effectiveness andvalidation monitoring of the project’s objectiveand the alternative’s proposed activitiesincluding mandated mitigation. This effortwould be followed up with the completion of theisland-wide eradication activities.

The window for bait application isNovember through December (late fall). Baitingmay begin as early as 2000. The late fall periodoffers the optimum time to apply the bait forthree reasons:

1) The endangered Brown Pelicans are notbreeding on the island;

2) The rats are in decline due to lack ofavailable food sources, which would causethem to eat the bait more readily.

3) The onset of the rainy season wouldexpedite the degradation of any residual baitnot consumed by the target species.

The chronology of proposed eradicationactivities is as follows:

2000 - 2001: During the application window ofNov-Dec, initiate eradication activities inrepresentative habitat within project area.

2001 – 2002: Complete Island-wide eradicationduring the Nov/Dec application window.

After treatment of East Islet andapproximately 20 ha of Middle Islet there maybe a need to retreat intermittently Middle Isletto prevent rats from re-invading East Island fromMiddle Island.

This proposed action would require FederalEnvironmental Protection Agency (EPA)

approval for use of rodenticide bait on theisland. A complete description of the proposedaction can be found in Chapter II – Alternativessection.

Emergency Response PlanThe emergency response plan (ERP) would

be implemented under the following conditions:

1) When it is suspected that rats may be onSanta Barbara Island.

2) After the eradication effort on AnacapaIsland has concluded.

The ERP has three main components with adecision process tied to each component. Thefirst component (Detection) focuses on theverification of presence of the rat. This is doneby intensive initial field investigation usingnormal rat detection techniques (chew baitblocks and sticks, trapping (live and snap, visualinspections, tracking tiles).

If rat presence is verified, the secondcomponent (Problem Evaluation) is a fieldinvestigation decision process that determinesthe extent of the rat problem, the terrainassociated with the rat territory, and the affectedresources within colonized area.

The third component (Problem Resolution)evaluates all of the factors (extent, terrain,affected resources) and through a decisionprocess makes a recommendation on the courseof action that is necessary to eradicate the rats.The decision process that takes place in all threecomponents is fully described in Chapter II –Alternatives.

PreventionAll rat introductions to the Channel Islands

have been through the assistance of humans.


CHAPTER ONE - 8

The most common ways rats are introduced tothe islands are:

1) Boats moored directly to the island oranchored nearby

2) Dinghies or other small boats pulled up onshore

3) Carried ashore in cargo such as foodstuffs,and building materials

4) Rafting ashore in flotsam

5) Shipwrecks

6) Planes and helicopters

Non-endemic mice are the most likelyspecies to reach the islands because of theirsmall size and habit of living in facilities andstorerooms, and are more likely to escapedetection. However, rats may occur morefrequently on large fishing vessels and otherboats.

To minimize the risk of rodent introductionsto the Channel Islands, a set of standards wouldbe implemented by the Park prior to conclusionof eradication activities on Anacapa Island. Theminimum proposed standards for the preventionof rodent invasion to the Islands are as follows:

1) Rodent proof storage areas.

2) Rodent proof containers that haul equipmentand supplies to the Islands.

3) Control rodents at all departure points,including planes, boats, and helicopters thattransport people and materials to the Islands(Park will work with concessionaires toaccomplish objectives when departure pointsare not under the control of the Park).

4) Inform and educate all people who visit theislands. This includes visitors,concessionaires, contractors, employees,permittees, and researchers.

Scope of the ProposedAction

This document focuses on three specificactions: 1) The activities that are necessary toeradicate rats from Anacapa Island, and 2) Theactivities necessary to respond to accidental ratintroductions to Anacapa and Santa BarbaraIsland, and 3) Preventing rodent introductions toall Park Islands.

This EIS does not cover the eradication of ratsfrom any other Park Island where rats havebecome established, specifically San MiguelIsland. Any eradication activity on San MiguelIsland would require additional NEPA analysisdue to the unique environmental issues associatedwith the island. Santa Barbara and AnacapaIslands have similar resources and resource issues.

Decisions to be MadeFor this EIS, the official responsible for

making the decision on which alternative isselected is the National Park Service RegionalDirection, Pacific West Region. The RegionalDirector, once the Final EIS has been completed,can decide to:

� Select one of the alternatives analyzed withinthe Final EIS, including the No-Actionalternative; or,

� Modify an alternative (for example, combineparts of different alternatives), as long as theenvironmental consequences of the modifiedaction have been analyzed within the FinalEIS.

Factors the Regional Director will take intoconsideration in making a decision are:

� Does the alternative meet National ParkService guidelines and policies, including theChannel Islands General Management Plan?


CHAPTER ONE - 9

� How well does the alternative meet the“Purpose and Need” for this project?

� How does the alternative respond to and/orresolve the environmental issues raised forthis project?

� The nature and extent of public comment tothe DEIS.


CHAPTER TWO - 10

........


CHAPTER TWOALTERNATIVES

Chapter ContentsINTRODUCTION ...................................................................................................................................................... 11ALTERNATIVE DEVELOPMENT PROCESS ........................................................................................................ 11

Internal Scoping and Public Involvement ............................................................................................................ 11Significant Environmental Issues......................................................................................................................... 12

Issue 1: Efficacy on Target Population .........................................................................................12Issue 2: Impact to Non-Target Species ..........................................................................................12

Sub-issue 1 - Marine Mammals ...............................................................................................................................13Sub-Issue 2 - Invertebrates (Marine/Terrestrial)......................................................................................................13Sub-Issue 3 - Marine Fishes ....................................................................................................................................14Sub-Issue 4 - Herpetofauna .....................................................................................................................................14Sub-Issue 5 - Seabirds .............................................................................................................................................14Sub-Issue 6 - Landbirds...........................................................................................................................................14Sub-Issue 7 - Mammals (Terrestrial) .......................................................................................................................15

Sub-Issue 8 - Flora ..................................................................................................................................................15Issue 3: Public Safety and Visitation .............................................................................................15

ALTERNATIVES CONSIDERED IN DETAIL........................................................................................................ 16INTRODUCTION ................................................................................................................................................. 16

FEATURES COMMON TO ALL ACTION ALTERNATIVES................................................................................... 16Effectiveness and Validation Monitoring ................................................................................................................16Non-native Rodent Introduction Prevention Plan....................................................................................................17Protection of Native Deer Mouse Population ..........................................................................................................17Rat Detection Response Plan...................................................................................................................................18Human Health ......................................................................................................................................................................... 18Timing .....................................................................................................................................................................18Permits and Approval ..............................................................................................................................................18Public Awareness ....................................................................................................................................................18

Visitation Restriction...............................................................................................................................................18 ALTERNATIVES……………………………………………………………………………… …………………19

ALTERNATIVE ONE - NO ACTION.................................................................................................................. 19ALTERNATIVE TWO - PROPOSED ACTION AND PREFERRED ALTERNATIVE................................................... 19ALTERNATIVE THREE.................................................................................................................................... 20ALTERNATIVE FOUR...................................................................................................................................... 22ALTERNATIVE FIVE ....................................................................................................................................... 23ALTERNATIVE SIX ......................................................................................................................................... 24

ALTERNATIVES CONSIDERED AND REJECTED .............................................................................................. 26BAIT STATIONS ................................................................................................................................................. 26ELEVATED BAIT STATIONS ............................................................................................................................... 26ALTERNATE RODENTICIDES.............................................................................................................................. 26TRAPPING.......................................................................................................................................................... 28INTRODUCING PREDATORS................................................................................................................................ 29

SUMMARY OF ALTERNATIVES........................................................................................................................... 29

ANACAP A ISLAND RES TOR AT ION PRO JEC TFIN AL ENV IRON MEN T AL IMP ACT ST AT E MEN T

CHAPTER TWO - 11

Introduction

This chapter describes the six alternatives tobe considered for implementation and identifiesthe significant environmental issues used toformulate these alternatives. The environmentalissues were developed as a result of extensive“scoping” conducted for this analysis. The“scoping” actions that were conducted for thisanalysis are described in detail. In addition, thischapter includes the rationale for dismissingother methods/alternatives from furtherconsideration. Chapter Four concludes with acomparison of alternatives.

Alternative DevelopmentProcess

Section 102(e) of NEPA states that allFederal agencies shall “study, develop, anddescribe appropriate alternatives to recommendcourses of action in any proposal which involvesunresolved conflicts concerning alternative usesof available resources”. In addition toresponding to unresolved conflicts, an EIS must“rigorously explore and objectively evaluate allreasonable alternatives” [40CFR 1502.14(a)].

Taken together, these requirementsdetermine the range of alternatives and providethe basis for the Deciding Official’s informeddecision, as required under NEPA. TheProposed Action, as stated in Chapter One, wasthe result of a resource analysis done by NPSresource management staff in collaboration withrodent eradication experts from the IslandConservation and Ecology Group (ICEG). Thiscollaborative effort identified managementactions necessary to respond to rat impacts onthe Anacapa Island ecosystem.

The alternatives detailed below weredeveloped to focus on the issues identified byresource specialists with the NPS, rat eradicationexperts and other rodent control experts,government regulatory agencies, and the generalpublic. Chapter Five – Consultation andCoordination lists all individuals, agencies andorganizations that provided substantivecomment regarding the proposed action.

Internal Scoping and PublicInvolvement

The NEPA “scoping” process [40CFR1501.7] was used to determine the scope of theanalysis and to identify potential issues andopportunities related to the Proposed Action. Asummary of the scoping and public involvementprocess for the proposed project and for therelease of the Draft EIS is summarized inChapter Five.

Below is a summary of the scoping that wasconducted to identify the environmental issuesto be considered for this project.

Proposed Action Internal Scoping The Park has an extensive record of

controlling rats on East Anacapa Island.Through these efforts, the Park has collectivelygained knowledge about the issues surroundingthe presence of rats on the island. In addition,the Park has funded scientific studies that focuson the ecology and control of rats within thePark.

Proposed Action External ScopingExternal scoping refers to the effort the Park

made to solicit input from the local public,organizations, other government regulatoryagencies. A complete summary of the Park’sscoping efforts can be found in Chapter Five.


CHAPTER TWO - 12

The methods the Park used to solicit inputincluded:

• Scoping Letter: A letter describing theproposed action was sent to individuals andorganizations who expressed interest in thePark’s management, and governmentagencies who might haveoversight/regulatory concerns about theproject.

• Public Meeting: On December 8, 1999 thePark hosted a public meeting. The Park paidfor ads in three local newspapersannouncing the meeting (Los AngelesTimes, Ventura County Star, Santa BarbaraNewspress). As part of this meeting thePark presented the need for the proposedaction as well as the proposed action.

• Presentations: The Park made presentationsto several local organizations.

• Website: The Park posted informationregarding the project on its website.

• Direct Communication: The Park madedirect communication to regulatorygovernment agencies who may haveoversight concerns regarding the project. Alist of these agencies can be found inChapter Five.

Significant EnvironmentalIssues

Through the Scoping and Public InvolvementProcess the following significant environmentalissues were identified. Significant issues arethose that may require project-specificalternatives, mitigation measures or designelements to address the potential effects of theproposed activities.

The issues are grouped into three broadcategories. Because these are broad categories,the “Non-target Impacts Issue” category willcontain a number of sub-issues. Each issue

category (-and/or sub-issue-) contains a summarystatement that defines the scope of the issue forthis project. In addition, for each issue category(and/or sub-issue), measurement indices are givento provide a preview of how the issue will beevaluated for direct, indirect, and cumulativeeffects for each alternative. The “Issue”categories are as follows:

� Issue 1: Efficacy on Target Species

� Issue 2: Non-Target Impacts

� Issue 3: Public Safety and Visitation

Issue 1: Efficacy on TargetPopulation

Efficacy for this analysis is defined as howwell the alternative would meet the 100%eradication objective.

Measurement Indices� Chemical and toxicological properties of

the rodenticide� Composition of the bait and how it is

applied� Local environmental factors.

Issue 2: Impact to Non-TargetSpecies

Chapter Four (EnvironmentalConsequences) will analyze both the potentialfor exposure of non-target species to rodenticideresidues and any physical disturbance fromnormal activities of non-target species caused byimplementation of the project.

Physical disturbance may occur due to baitingactivities, and crews walking around the island.For example, Malacothrix squalida, a listedspecies (endangered) under the endangeredSpecies Act is located in the project area. As suchthe Park is required to consult with the USFWS onpotential impacts the project may have on thespecies. Physical disturbance from monitoring


CHAPTER TWO - 13

activities is the only potential impact that mayoccur to this species

Rodenticide exposure, for the purpose of thisanalysis, can occur through direct baitconsumption (primary exposure), secondarily (viacarcasses containing rodenticide residues) andpossibly tertiary exposure. Primary exposureoccurs when organisms feed directly on the bait.Secondary exposure occurs when animals feed onprimarily exposed organisms with residues in theirtissue. Tertiary exposure is possible, throughconsumption of a secondarily exposed organism,but has not been thoroughly documented in theliterature (Eason and Murphy 1999). For thepurpose of this analysis, only primary andsecondary exposure will be evaluated.

The first step in the process to determinewhich non-target species may be impacted by theproposed action was to identify all the knownspecies within the project area. The species werethen placed in a taxonomic classification toidentify logical groups of species. Based on therisk assessments for the rodenticide (and otherscientific studies) the groups of species that maybe impacted were identified. These identifiedgroups (See Table 1) will be carried forward in theanalysis as “Sub-Issues”.

The taxonomic classification foridentification of sub-issues is necessary toprovide a logical layout of “effects” whenevaluating toxicological risk. This is becausethe toxicology of these rodenticides is consistentwithin the groups that have been identified. Thesub-issues as derived from Table 1 is as follows:

Sub-Issue 1: Marine MammalsTwo pinniped species (harbor seals, Phoca

vitulina, and California sea lions, Zalophuscalifornianus) haul out on the rocks and beachesaround Anacapa Island. Harbor seals breed onthe island between January and March. Bothspecies may be disturbed by the baiting activitiesand possibly by some of the monitoring

activities. Efforts would be made to minimize

drift of bait into the marine environment;however, if bait does enter the ocean, marinemammals may be at risk of rodenticideexposure.

� Measurement Indices

� Exposure to Residues – the effectsdiscussion will focus on how theproposed action and alternatives wouldexpose the marine mammals torodenticide residues.

Sub-Issue 2: Invertebrates(Marine/Terrestrial)

Terrestrial invertebrates on Anacapa Islandwould likely consume carcasses of vertebratesexposed to the rodenticide, as well as anyresidual bait not consumed. Thus, there ispotential for the transfer of residues into thefood chain.

Table 1. Project Area Species TaxonomicClassification______________________________

I. MarineA. Mammals (Sub-Issue 1)B. Invertebrates (Sub-Issue 2)C. Fishes (Sub-Issue 3)

II. TerrestrialA. Fauna

1. Invertebrates (*combined with Sub-Issue 2)

2. Herpetofauna (Sub-Issue 4)3. Avian

a. Seabirds (Sub-Issue 5)b. Landbirds (Sub-Issue 6)

4. Mammals (Sub-Issue 7)B. Flora (Malacothrix squalida) (Sub-Issue 8)

____________________________________


CHAPTER TWO - 14

Rodenticide may enter the marine foodchain if bait incidentally drifts into theintertidal/subtidal areas and is consumed bymarine intertidal invertebrates.


� Exposure to Residues – the effectsdiscussion will focus on how the proposedaction and alternatives will expose theinvertebrate populations to rodenticideresidues, and, will analyze those predators atrisk.

Sub-Issue 3: Marine FishesThe relative exposure of gamefish to the

rodenticide is small; however, there is a risk ofincidental drift of bait into the marineenvironment thus presenting a primary andpossible secondary exposure risk.

Measurement Indices

� Exposure to Residues – the effectsdiscussion will focus on how theproposed action and alternatives wouldexpose gamefish to the rodenticide viabait ingestion using recent studies withplacebo baits.

Sub-Issue 4: HerpetofaunaAnacapa is home to two species of reptiles,

the Side-blotched lizard (Uta stansburiana) andthe Southern Alligator lizard (Elgarramulticarinata ), and one species of salamander –the Channel Islands Slender Salamander(Batrachoseps pacificus). These species aresubject to primary and secondary exposure risk.


� Exposure to Residues – The effectsdiscussion will focus on how theproposed action and alternatives wouldimpact lizards and amphibianpopulations, with emphasis onpopulation level impacts and inclusion

of results from eradication programselsewhere.

Sub-Issue 5: SeabirdsFor the purpose of this analysis, the seabirds

have been subdivided into two groups: thepelagic seabirds and roosting seabirds. Thepelagic seabirds are those birds that resideoffshore from Anacapa Island and only utilizethe island for breeding, outside of the proposedbaiting period. The roosting seabirds are thosethat utilize Anacapa for roosting during theproposed baiting period.


� Federally Endangered Seabirds –Roosting and nesting habitat for theendangered Brown Pelican exists withinthe analysis area. The effects discussionwill describe how the proposed actionand alternatives to the proposed actionaffect the Brown Pelican.

� Disturbance – the effects discussion in theeffects will focus on how the proposedaction and alternatives would disturbseabirds.

� Exposure to Residues– The effectsdiscussion will focus on how theproposed action and alternatives wouldimpact seabirds, with results from recentstudies completed on Anacapa Island.

Sub-Issue 6: LandbirdsSome species of landbirds utilize Anacapa

Island seasonally and others year round. For thepurpose of this analysis, the landbirds have beendivided into two groups: the birds of prey,(raptors); and passerines. Birds of prey are atrisk of secondary exposure through consumptionof primarily exposed organisms. The Passerineswere subdivided further based on foragingstrategy (i.e. omnivorous, insectivorous, and


CHAPTER TWO - 15

granivorous). While the insectivorouspasserines are at risk of secondary exposure andthe granivorous are at risk of primary exposure,the omnivorous passerines are at risk of bothprimary and secondary exposure.


� Exposure to Residues - The effectsdiscussion will describe how theproposed action and alternatives to theproposed action may affect individualbirds of prey and passerines.

Sub-Issue 7: MammalsThe endemic subspecies (unique to Anacapa

Island) of the Deer Mouse (Peromyscusmaniculatus anacapae) co-exists on AnacapaIsland with the introduced rats. Mice sharemany characteristics with rats and thus, are at ahigh risk of primary exposure.


� Exposure to Residues – The effectsdiscussion will focus on how theproposed action and alternatives wouldimpact the Deer Mouse population, withemphasis on population level impactsand include the results of rodent controloperations elsewhere.

Sub-Issue 8: FloraThe endangered Island Malacothrix

(Malacothrix squalida) is an annual herb fromthe aster family. It is found on Santa CruzIsland and Middle Anacapa Island. This annualoccurs on rocky coastal bluffs in coastal scrub(Junak et al. 1995). On Middle Anacapa Islandthe distribution is very limited. It is found intwo locations, near the east and west end ofMiddle Anacapa Island. The presence of islandmalacothrix makes it highly susceptible totrampling from personnel walking on the island.


� Trampling – The effects discussion willfocus on how the proposed action andalternatives would impact the islandmalacothrix population, with emphasis onmitigation against damage.

Issue 3: Public Safety and VisitationAnacapa Island is the most visited of all

islands in the Channel Islands National Park.Visitors are only allowed access to East Islandand Frenchy’s Cove on West Island. East Islandreceives both day visitors and overnightcampers. With the high visitation to the islandsby the public there are two concerns: 1) potentialexposure of the public to the rodenticide: and 2)impacts to visitors from closing the islandduring operations of the AIRP.


� Exposure to Residues: The effectsdiscussion will focus on how theproposed action and alternatives wouldpotentially expose the visiting public tothe rodenticide, as well as the associatedhealth risks of exposure.

� Visitor Impacts: The effects discussionwill focus on how the proposed actionand alternatives would potentially impactvisitors’ enjoyment of the Park duringAIRP operations.

Issues Dismissed from AnalysisThe analysis considered the social impacts

of implementing the proposed project. Theanalysis concluded that the proposed projectwould not change the local population’s work,recreation, or social interactions. As such,executive order 12898 (environmental justice)does not apply to this analysis.

Similarly, this analysis does not affectfloodplains (EO1508.27), or sacred sites


CHAPTER TWO - 16

(EO13007). The Park has also determined thatthis analysis does not require analysis of energyrequirements (1502.16), nor does it require aeconomic impact analysis (EO11821)

Alternatives Considered inDetail

IntroductionDevelopment of the alternatives was

strongly influenced by the significantenvironmental issues. In developing thealternatives, the Park consulted many outsideexperts in the field of vertebrate biology,toxicology, and avian biology. In addition to thesix alternatives described below, many otheralternatives were considered, but wereeliminated from further study. Thesealternatives, along with the rationale for theirdismissal, can be found at the end of this chapterunder the heading, “Alternatives Considered butDismissed”. Because of the specific objectiveof this project, many alternatives were dismissedbecause they could not meet the objective oftotal eradication.

Eradicating rats from Anacapa Island, and theeradication of rats as a result of an accidentalintroduction are two distinct, but inter-relatedactivities. The former comprises the actionsbeing proposed for the eradication of the knownand long-term persistent rat population onAnacapa Island. The latter comprises theactivities that are being considered in response tothe accidental introduction of rats to islands withinthe Park.

Features Common to All ActionAlternatives

Effectiveness and ValidationMonitoring

Effectiveness and validation monitoringwould be required to be done for each actionalternative prior to final treatment of Middle andWest Islets. Effectiveness monitoring would beconducted to determine if the alternative’sprescription is effective in meeting the statederadication objective. Validation monitoringwould be conducted to determine if theenvironmental effects of implementing themanagement action (including mitigationmeasures) are similar to the effects predicted inthe EIS.

For each alternative, eradication wouldbegin with baiting (consistent with thealternative) in a representative habitat within theproject area. Representative habitat would belimited to East Islet as a whole, or a smaller areaon Middle Islet.

Analysis of monitoring data would be doneprior to proceeding with final treatment ofMiddle and West Islets. Evaluation ofmonitoring results would determine whether to:

• Modify the eradication activities

• Continue the proposed eradication activities

Monitoring results that lead to amodification of the project may require asupplemental EIS. The supplemental EIS andsubsequent decision would need to be preparedprior to resumption of eradication activities. Asupplemental EIS is necessary when substantialnew information is discovered, and/or whenchange of activities result in substantial changein environmental effects that were notpreviously analyzed in the EIS.

Monitoring results that are consistent withthe analysis provided in the FEIS would allow


CHAPTER TWO - 17

for the continuance of the proposed eradicationactivities without additional environmentalcompliance.

Non-native Rodent IntroductionPrevention Plan

To minimize the risk of rodent introductionsto the Channel Islands, a set of standards wouldbe implemented by the Park. The minimumproposed prevention actions, which wouldbecome the Park’s prevention plan, are asfollows:

1) Rodent-proof storage areas.

2) Rodent-proof containers that haul equipmentand supplies to the Islands.

3) Control rodents at all departure points,including planes, boats, and helicopters thattransport people and materials to the Islands.

4) Inform and educate all people who visit theislands. This includes visitors,concessionaires, contractors, employees,permittees, and researchers.

Protection of Native Deer MousePopulation

The presence of the endemic Anacapa DeerMouse represents a unique challenge to rateradication. The conservation and managementof Anacapa Island Deer Mice is a high priority forthe AIRP. The genetic and morphological statusof the Anacapa Deer Mouse has been investigatedusing genetics, morphometrics and computermodeling (Pergams et al. 2000). The results ofthis study has confirmed that the Anacapa DeerMouse is a distinct subspecies that is geneticallyidentical across all three islets. Thus, the DeerMouse population can be managed as a wholepopulation (one “evolutionarily significant unit”(ESU)) rather than a distinct population on eachislet. Further, to maintain genetic diversity andensure a viable population, 1000 mice across all

three islets would need to be protected (Pergamset al. 2000). Management actions to protect theDeer Mouse population will include a protectionplan that will be implemented prior to theeradication efforts. Consultation with Peromyscusand genetic experts from the Brookfield Zoo,Illinois and the University of Illinois is underwayto develop a protection plan that will maintaingenetic diversity and ensure a viable population ofmice on each islet post eradication. TheEffectiveness and Validation Program will aid inthe development of an effective protection planfor the Anacapa Deer Mouse because it willidentify problem areas that would allow changesto the final Deer Mouse protection plan. Thefinal Deer Mouse protection plan would beimplemented prior to completion of the baiting.The Deer Mouse protection plan may include oneor a combination of the following:

1. Laboratory captive holding/breedingon/off island: Mice are live captured andtransported to a laboratory holding facilityeither on island or on the mainland. About350 mice from each islet are captured fromeach island and held. They would bereleased back on to the island over time.

2. Move mice between islands: Mice aremoved from Middle and/or West Island toEast Island in between treatment of East andMiddle/West Islands. Thus, a viablepopulation of mice are available on EastIsland for restocking Middle and WestIslands after eradication.

3. Fenced enclosures: Mice are maintainedin a fenced enclosure where rats areprevented from entering, and mice areprevented from entering or leaving. Acomplement of mice are maintained withrodent chow and water for a determinantperiod of time. Mice are released over timefrom the enclosure back into the Anacapaenvironment, restocking the island. Theenclosure area would not be treated.


CHAPTER TWO - 18

Rat Detection Response PlanReacting to a “rat-spill” from a shipwreck or

some other introduction requires a rapid response,as does any appearance of rats on Anacapa Islandfollowing eradication, or on Prince, Sutil andSanta Barbara Islands. In the event of ashipwreck the Shipwreck Response Plan is adecision pathway to implement the Rat DetectionResponse Plan (Appendix A) – a plan to evaluatethe extent of rodent introduction and implementan appropriate response. The Rat DetectionResponse Plan would be implemented if rats wereintroduced to the islands via shipment of goods orequipment.

Human HealthA buffer of approximately 10 meters around

the campground, buildings and landing area onEast Island would be established. This bufferwould not be aerially treated, although, aperimeter of bait stations would be establishedapproximately every 10-15 m. Each stationwould be uniquely labeled to identify itslocation. An appropriate warning label such as:“Anacapa Island Restoration Project. RatPoison – Danger, Do Not Disturb. Contact ParkRanger or telephone 805-658-5720” on eachstation and a copy of the product label wouldalso be included at each of these bait stations forreference.

Timing To minimize both disturbance and potential

ecotoxicological impacts, bait application wouldbe restricted to September through December ofeach year.

The late fall period offers the optimum timeto apply the bait for the following reasons: 1)endangered Brown Pelicans are not breeding onthe island; 2) the rats are in decline due to foodstress and therefore would eat the bait morereadily; and 3) the onset of the rainy season

would expedite the degradation of any residualbait not consumed by the target species.

Splitting the treatment of the islands into twoyears is beneficial for several reasons. First, itallows monitoring for efficacy, i.e. evaluate thefeasibility of eradication at the maximum of 15kg/ha sowing rate, and modify and improveoperational procedures for year 2. Secondly, thePark can monitor impacts to non-target specieson a smaller scale to identify further necessarymitigation measures.

Permits and ApprovalEPA registration and approval would be

required for implementation of any of thealternatives considered in this analysis (except theNo Action alternative). Under the FederalInsecticide, Fungicide, and Rodenticide Act(FIFRA), use of a non-registered rodenticiderequires approval from the Federal EPA. A site-specific application label would be prepared forthe AIRP project. Consultation and registrationwith the EPA is required before application.

Public AwarenessPosters outlining the project and warning

visitors of the activities on the island would beposted on the mainland at the visitor center, onisland at the landing cove and at the visitorcenter at East Anacapa Island.

Visitation RestrictionThe operations of the eradication program

will require that visitation be restricted for ashort period. East Anacapa Island will beclosed to all visitors for approximately 2-3 days.The restriction is necessary to allow theoperations crews to implement the baitingoperation including helicopter activity,evaluation, and monitoring of the environment.

After the operations are complete, the islandwill be open to day use visitors. East Anacapa


CHAPTER TWO - 19

will be closed to campers for approximately 5days because the campground will be used forhousing the post treatment monitoring crews.

Alternatives

Alternative OneNo Action

Alternative One (no action) continues theexisting rat management strategy on AnacapaIsland. Implementation of this alternative wouldoccur assuming that future Park budgets aresimilar to recent budgets. Analysis of thealternative is a requirement of the NationalEnvironmental Policy Act (NEPA) and NationalPark Service planning procedures.

The existing management strategy formanaging the species Rattus rattus on AnacapaIsland is found in the Park’s GeneralManagement Plan. Specifically, the GMP states,“Based on research and experimentation,programs will be implemented to reduce to theextent feasible the impacts of introduced plantand animal species.” From the late 1980’sthrough the early 1990’s, concentrated controlactivity occurred on Anacapa Island. Thisconsisted of widely spaced, elevated bait stationsusing the rodenticide Warfarin. Since that timethe Park has concentrated control efforts aroundthe existing structures on East Island. Nocontrol measures have been taken outside ofthese areas due to budget, personnel, andcompliance constraints.

Alternative Two (PreferredAlternative)Aerial broadcast of a Rodent BaitContaining Brodifacoum

Summary

This alternative outlines the use of a rodentbait aerially broadcast from a hopper suspendedunder a helicopter, and broadcast by hand.

East Islet baiting would occur during theNov/Dec treatment window and would betreated along with approximately 20 ha ofMiddle Islet to lower the probability of invasionby rats from Middle Islet to East Islet. The 20ha section of Middle Islet may be treatedintermittently to prevent re-invasion of EastIslet. Middle Islet (including the section treatedwith East Islet ) and West Islet would be treatedduring the application window of Novemberthru December in the year following East Isletapplication. Bait would be applied in thefollowing formulation:

Active Ingredient: Brodifacoum

Concentration of Active Ingredient: 25 ppmBrodifacoum

Rate of application: Bait would be broadcast at amaximum rate of 15 kg /ha

Application: Application would be completedby hand or aerial broadcast across 100% of thearea of the islands. Hand broadcast would becarried out by or under the supervision oflicensed applicators spreading bait by hand.Aerial broadcast would be carried out utilizing ahopper (dry slinger) suspended from a helicopterflying along a predetermined pathwayprogrammed into a Differential GPS. Aerialbaiting would be carried out using a licensedpesticide applicator.

Top of Island: Bait would be spread from ahopper suspended under a helicopter. Thehelicopter would fly at approximately 50 knots,approximately 25-50 m aboveground with the


CHAPTER TWO - 20

hopper open and spreading bait. To ensure evencoverage, the island would be flown twice: oncein an East-West direction sowing at half the rate,then again on a North-South direction sowingbait at half the rate. Bait would be spread fromthe hopper in a 360-degree pattern. The numberof passes over the island would be determinedby the swath width which is a function of size ofthe bait pellet and speed with which it ispropelled out of the hopper.

Cliffsides: Every effort would be made toprevent bait from drifting into the marineenvironment. The helicopter would fly alongthe top cliff edge to minimize drift of bait intothe marine ecosystem. The helicopter alsowould be used to “trickle” bait to the largeroffshore rocks with the helicopter hovering low,hopper turned off- gate open to ensure adequatecoverage. In some cases, bait would be handbroadcast onto the cliffsides from above. In thecases of hard-to-reach offshore rocks and lowerreaches of cliffsides, travel by boat for handbroadcast may be required.

Number of applications: A maximum of twoapplications is anticipated.

Timing

• Years 1-2: Initiate eradication by baitingin representative habitat during theNovember-December applicationwindow (either East Islet as a whole, orsmaller area on Middle Islet) and conductimplementation and effectivenessmonitoring. Monitor results anddetermine if changes are necessary. Year1 activities may begin during the 2000Nov-Dec application window given thatnecessary compliance measures arecompleted.

• Years 2-3: If monitoring results provefavorable, proceed with island-wideeradication activities.

East Islet bait broadcast including 20 haof Middle Islet, subsequent yeartreatment of Middle and West Islet,including the 20 ha buffer on MiddleIslet. If rats are detected on EastAnacapa Island between treatmentperiods, the Rat Detection Response Planmay be implemented. If the problemevaluation demonstrates that rats arewidespread on East Island, the wholeisland may be re-treated during thetreatment of Middle and West Islands.

• Future: If rats are detected, the RatDetection Response Plan would beimplemented (See Appendix A).

Alternative ThreeBait Stations for Top of Island and AerialBroadcast the Cliffsides with Brodifacoum

Summary

The primary objective of this alternative is tominimize primary exposure impacts tolandbirds. This alternative outlines a stratifiedbaiting technique where bait stations would beused on top of Middle and East Islands whileaerial broadcast is used on West Island and thecliffsides of East and Middle Islands. The baitstations would be armed for one year prior totreatment of West Island and cliffsides of Eastand Middle Islands. Under this strategy, ratswould have been removed from the top of theislet for one year prior to treating the cliffsides.West Island would not be treated with baitstations because of the steep terrain and potentialdisturbance to pelicans with frequent visits byoperators.

The top areas of East and Middle Isletswould be initiated in Year 1 with deploymentand arming of bait stations. In Year 2, baitstations would be checked and re-armed, whilethe cliffsides of East and Middle and all of WestIsland would be treated by hand and aerial


CHAPTER TWO - 21

broadcast with a second generationanticoagulant.

Active Ingredient: Brodifacoum

Concentration of Active Ingredient: 25 ppm

Aerial Application:

• Rate of Application: maximum of 15kg/ha

• Number of Applications: a maximum oftwo applications.

Bait Stations Application:

• Rate of Application: 6 bait blocks/station

• Number of Applications: re-armed untilactivity ceases

Bait Station Design and Construction: Baitstations would be standard lockable stations,similar to those used by professional pest controloperators, but brightly colored to assist locatingin dense shrubbery.

Bait Station Locations: Bait stations would besecured in place around the cliff edge at 25-50 mintervals completely encircling the top of theisland. The remaining bait stations would besecured on top of the island, laid out on a grid(spacing at 50 x 50 m). Each station would beuniquely marked with a tag identifying itslocation and an appropriate warning such as“Anacapa Island Restoration Project: Rat Poison– Danger, Do Not Disturb. Contact Park Rangeror phone 805 658 5720”.

Bait Station Arming and Checking: Each baitstation would be armed on the same day oncethe program is initiated. Certified pesticideapplicators would supervise the arming of eachstation with six bait blocks containing 25-ppmbrodifacoum. Each station would be visiteddaily, checked, and bait replenished to the 6-block level as necessary until activity ceases(activity includes bait chewed or taken by rats).Data (number of blocks taken, chewed, added,or replaced) from each station would be

collected and entered into a database foranalysis. When activity (bait removal orconsumption) ceases, bait stations would bechecked and re-armed bi-weekly then monthlyfor one year, documenting bait take and rat signin stations.Timing:

• Years 1-2: Initiate eradication by baitingas prescribed in representative habitatduring the Nov-Dec application window(either East Islet as a whole, or smallerarea on Middle Islet) and conductimplementation and effectivenessmonitoring. Monitor results anddetermine if changes are necessary. Year1 activities may begin during the 2000Nov-Dec application window given thatnecessary compliance measures arecompleted.

• Year 2-3: If monitoring results provefavorable, proceed with island-wideeradication activities.

Deploy and arm bait stations on the flat,accessible top of East and Middle Islets.The stations would be checked daily, andre-armed as necessary, until activityceases. Continue monitoring stations on abi-weekly then monthly basis. Refresh baitin stations on East and Middle Islands,aerially broadcast rodenticide baitcontaining 25 ppm brodifacoum oncliffsides of East and Middle Islands andthe 100% aerial broadcast treatment ofWest Island. The application rate wouldbe up to 15 kg/ha following proceduresoutlined in Alternative Two. Continue tocheck and re-arm bait stations at bi-monthly intervals for an additional year.

• Year 2 - Future: If rat sign is found, theRat Detection Response Plan would beimplemented (Appendix A).


CHAPTER TWO - 22

Alternative FourAerial broadcast of a Rodent BaitContaining BromadioloneSummary

This alternative involved aerial broadcast ofbromadiolone, a second-generationanticoagulant similar to brodifacoum. Thisalternative addresses the issue of potentialimpacts to non-target species.

The rodent bait would be aerially broadcastfrom a hopper suspended under a helicopter, andhand broadcast by workers of the AnacapaIsland Restoration Project (AIRP).

The treatment of Anacapa Island would takeplace over a period of one year. East Anacapawould be treated in year one along withapproximately 20 ha of Middle Anacapa Islandto lower the probability of invasion by rats fromMiddle Islet to East Islet. The 20 ha section ofMiddle Island may be treated periodically toprevent re-invasion of East Island. MiddleIsland (including the section treated in year one)and West Island would be treated in year 2.

Active Ingredient: Bromadiolone


Rate of application: Bait would be broadcast at amaximum rate of 15 kg /ha.

Application: Application would be completedby hand or aerial broadcast across 100% of thearea of the islands. Hand broadcast would becarried out by or under the supervision oflicensed applicators spreading bait by hand.Aerial broadcast would be carried out (by alicensed pesticide applicator) utilizing a hopper(dry slinger) suspended from a helicopter flyingalong a predetermined pathway programmedinto a Differential GPS.

Top of Island: Bait would be spread from ahopper suspended under a helicopter. Thehelicopter would fly at approximately 50 knots,approximately 25-50 m aboveground with the

hopper open and spreading bait. To ensure evencoverage, the island would be flown twice: oncein an East-West direction sowing at half the rate,then again on a North-South direction sowingbait at half the rate. Bait would be spread fromthe hopper in a 360-degree pattern. The numberof passes over the island would be determinedby the swath width which is a function of size ofthe bait pellet and speed with which it ispropelled out of the hopper.

Cliffsides: Every effort would be made toprevent bait drifting into the marineenvironment. The helicopter would fly alongthe top cliff edge to minimize drift of bait intothe marine ecosystem. The treated area would bea portion of the top of the island and thecliffsides. In some cases, hand broadcast baitonto the cliffsides from above, or travel by boatto service the offshore rocks, islands, and lowerreaches of the cliffsides may be necessary. Thehelicopter would be used to “trickle” bait thelarger offshore rocks with the helicopterhovering low, hopper turned off- gate open toensure adequate coverage.


Timing:• Years 1-2: Initiate eradication by baiting

as prescribed in representative habitatduring the Nov-Dec application window(either East Islet as a whole, or smallerarea on Middle Islet) and conductimplementation and effectivenessmonitoring. Monitor results anddetermine if changes are necessary. Year1 activities may begin during the 2000Nov-Dec application window given thatnecessary compliance measures arecompleted.



CHAPTER TWO - 23

Initiate broadcast of bait onto EastIsland and the 20 ha buffer of MiddleIsland. Initiate broadcast of bait ontoMiddle and West Island including the 20ha buffer on Middle Island. If rats aredetected on East Anacapa Islandbetween year one treatment and year 2treatment, the Rat Detection ResponsePlan may be implemented. If theproblem evaluation demonstrates thatrats are widespread on East Island, thewhole island may be re-treated duringthe treatment of Middle and WestIslands. The 20 ha section of MiddleIsland may be treated periodicallybetween year one and treatment year 2to prevent re-invasion of rats to EastIsland. This 20 ha section of MiddleIsland would be re-treated during thetreatment of Middle Island.

• Year 2- Future: If rats are detected, theRat Detection Response Plan would beimplemented (Appendix A)

Alternative FiveBait Stations for Top of Island and AerialBroadcast the Cliffsides withBromadioloneSummary

The primary objective of this alternative is tominimize primary exposure impacts to landbirdsand spatially exclude Deer Mice from gainingaccess to bait in stations. This alternativeoutlines a stratified baiting technique where baitstations would be used on top of Middle andEast Islands while aerial broadcast is used onWest Island and the cliffsides of East andMiddle Islands. The bait stations would bearmed for one year prior to treatment of WestIsland and cliffsides of East and Middle Islands.Under this strategy, rats would have beenremoved from the top of the islet for one yearprior to treating the cliffsides. West Island

would not be treated with bait stations becauseof the steep terrain and potential disturbance topelicans with frequent visits by operators.

The top areas of East and Middle Islets would beinitiated in Year 1 with deployment and armingof bait stations. In Year 2, bait stations wouldbe checked and re-armed, while the cliffsides ofEast and Middle and all of West Island would betreated by hand and aerial broadcast with asecond generation anticoagulant.

Active Ingredient:

• Bait Stations: bromadiolone

• Aerial Broadcast: bromadiolone


Aerial Application:

• Rate of Application: 15kg/ha

• Number of Applications: a maximum of 2applications is anticipated

Bait Stations Application:

• Rate of Application: Stations would bearmed with 6 bait blocks per station

• Number of Applications: Stations wouldbe re-armed until activity ceases.

Bait Station Design and Construction: Baitstations would be standard lockable stations,similar to those used by professional pest controloperators, but brightly colored to assist locatingin dense shrubbery.

Bait Station Locations: Bait stations would besecured in place around the cliff edge at 25 mintervals completely encircling the top of theisland. The remaining bait stations would besecured on top of the island, laid out on a grid(spacing at 50 x 50 m). Each station would beuniquely marked with a tag identifying itslocation and an appropriate warning such as“Anacapa Island Restoration Project: Rat Poison– Danger, Do Not Disturb. Contact Park Rangeror phone 805 658 5720”.


CHAPTER TWO - 24

Bait Station Arming and Checking: Each baitstation would be armed on the same day oncethe program is initiated. Certified pesticideapplicators would supervise the arming of eachstation with six bait blocks containing 50-ppmbromadiolone. Each station would be visiteddaily, checked, and bait replenished to the 6block level as necessary until activity ceases(activity includes, bait chewed or taken by rats).Data (number of blocks taken, chewed, added,replaced) from each station would be collectedand entered into a database for analysis. Whenactivity (bait removal or consumption) ceases,bait stations would be checked and re-armed bi-weekly then monthly for one year, documentingbait take and rat sign in stations.

Timing:

• Years 1-2: Initiate eradication by baitingas prescribed in representative habitatduring the Nov-Dec application window(either East Islet as a whole, or smallerarea on Middle Islet) and conductimplementation and effectivenessmonitoring. Monitor results anddetermine if changes are necessary. Year1 activities may begin during the 2000Nov-Dec application window given thatnecessary compliance measures arecompleted.


Deploy and arm bait stations on the flat,accessible top of East and Middle Islets.The stations would be checked daily, andre-armed as necessary, until activityceases. Continue monitoring stations on abi-weekly then monthly basis. Refresh baitin stations on East and Middle Islandsstations, aerially broadcast rodenticidebait containing 25 ppm brodifacoum oncliffsides of East and Middle Islets andthe 100% aerial broadcast treatment of

West Island. The application rate wouldbe up to 15 kg/ha following proceduresoutlined in Alternative Two. Continue tocheck and re-arm bait stations at bi-monthly intervals for an additional year.

• Year 2 - Future: If rat sign is found, theRat Detection Response Plan would beimplemented (See Appendix A).

Alternative SixAerial broadcast of a Rodent BaitContaining Diphacinone followed by aRodent Bait Containing Brodifacoum

Summary

This alternative outlines the aerial broadcastof diphacinone, a first generation anticoagulantfollowed by a bait containing brodifacoum, asecond-generation anticoagulant. Thisalternative addresses the issue of potentialprimary and secondary exposure impacts to non-target species.

The rodent baits would be aerially broadcastfrom a hopper suspended under a helicopter, andby hand.

East Islet baiting would occur during theNovember thru December window and would betreated along with approximately 20 ha ofMiddle Islet to lower the probability of invasionby rats from Middle Islet to East Islet. The 20ha section of Middle Islet may be treatedintermittently to prevent re-invasion of EastIslet. Middle Islet (including the section treatedwith East Islet ) and West Islet would be treatedduring the application window of Novemberthru December in the year following East Isletapplication. Bait would be applied in thefollowing formulation:

Active Ingredients: Diphacinone andBrodifacoum


CHAPTER TWO - 25

Concentration of Active Ingredient:

• Diphacinone: 50 ppm

• Brodifacoum: 25 ppm

Rate of application:

• Diphacinone: 22-34 kg/ha

• Brodifacoum: 5-10 kg/ha

Application: The first application ofdiphacinone would be applied in two wavesapproximately 3-4 weeks apart.

Three to four weeks after final diphacinoneapplication, the brodifacoum bait would beaerially broadcast at a rate of 5-10 kg/ha.

Application would be completed by hand oraerial broadcast across 100% of the area of theislands. Hand broadcast would be carried outwith or under the supervision of licensedapplicators spreading bait by hand. Aerialbroadcast would be carried out utilizing a hopper(dry slinger) suspended from a helicopter flyingalong a predetermined pathway programmedinto a Differential GPS.

Top of Island: Bait would be spread from ahopper suspended under a helicopter. Thehelicopter would fly at approximately 50 knots,approximately 25-50 m aboveground with thehopper open and spreading bait. To ensure evencoverage, the island would be flown twice: oncein an East-West direction sowing at half the rate,then again on a North-South direction sowingbait at half the rate. Bait would be spread fromthe hopper in a 360-degree pattern. The numberof passes over the island would be determinedby the swath width which is a function of size ofthe bait pellet and speed with which it ispropelled out of the hopper.

Cliffsides: Every effort would be made toprevent bait drifting into the marineenvironment. The helicopter would fly alongthe top cliff edge to minimize drift of bait intothe marine ecosystem. The treated area would be

a portion of the top of the island and thecliffsides. In some cases, hand broadcast baitonto the cliffsides from above, or and travel byboat to service the offshore rocks, islands, andlower reaches of the cliffsides may be necessary.The helicopter would be used to “trickle” baitthe larger offshore rocks with the helicopterhovering low, hopper turned off- gate open toensure adequate coverage.


Timing:

• Year 1-2: Initiate eradication by baitingas prescribed in representative habitatduring the Nov-Dec application window(either East Islet as a whole, or smallerarea on Middle Islet) and conducteffectiveness and validation monitoring.Monitor results and determine if changesare necessary. Year 1 activities maybegin during the 2000 Nov-Decapplication window given that necessarycompliance measures are completed.


Initiate broadcast of bait onto EastIsland and the 20 ha buffer of MiddleIsland. .Initiate broadcast of bait ontoMiddle and West Island including the 20ha buffer on Middle Island. If rats aredetected on East Anacapa Islandbetween year one treatment and year 2treatment, the Rat Detection ResponsePlan may be implemented. If theproblem evaluation demonstrates thatrats are widespread on East Island, thewhole island may be re-treated duringthe treatment of Middle and WestIslands.


CHAPTER TWO - 26

• Year 2- Future: If rats are detected, theRat Detection Response Plan would beimplemented (See Appendix A)

Alternatives Consideredand Rejected

Bait StationsUnder this alternative bait stations would

have been placed on top as well as on cliffsidesand shorelines of Anacapa Island. This wasdismissed because of the steep topography andunstable cliffsides, would have made stationsproblematic. Moreover, vegetation would havebeen trampled and nesting pelicans disturbed.A detailed description of each reason follows.

Anacapa Island is composed of basalt and ispartially volcanic in origin. As a result, thecliffsides are extremely unstable and rockfallsare not uncommon. The placement of baitstations would require project personnel to scalethe cliffs using ropes. The instability of thecliffsides and high risk of rocks falling on, andseverely injuring climbers resulted in thisalternative being dismissed.

Bait stations would have to be servicedfrequently by personnel, resulting in a high riskof erosion and trampling of native vegetation. Anetwork of trails would be created that wouldresult in long-term damage.

Disturbance to pelicans nesting on WestAnacapa would be unavoidable because of theneed to service bait stations. The pelicans areprotected under the Endangered Species Act andregular disturbance could cause nestabandonment and nest failure resulting in lowproductivity.

Elevated Bait StationsThe use of elevated bait stations, designed by

Erickson (1990) would have been used in any ofthe alternatives that required bait stations.

Erickson’s (1990) laboratory study showedthat only 93% (n=30) of roof rats could gainaccess to the bait in the stations. The purposeand need dictates that 100% be removed;therefore, elevated bait stations fail to meet theobjective. In the field, rats were shown toreadily use the stations; however, it was unclearif 100% of rats in the area were exposed to thebait. Although the elevated bait stations showpromise for rat control where native mice arepresent, Erickson (1990) did not demonstratethat rats could be controlled or eradicated fromAnacapa Island.

Using elevated bait stations would requirepersonnel to dig PVC piping into the ground tosupport the stations. Where soil is present, PVCmay be easily dug into the ground. However,Anacapa is very rocky (the majority of the islandis exposed rock), thus digging holes for PVCwould be near impossible. In addition to thelogistical challenge the placement of stationsacross the islands and cliffsides would present,they also would cause disturbance to nativevegetation and disturbance and possible damageto cultural sites (e.g. Chumash native middens,archaeological sites).

Alternate RodenticidesThe use of the other rodenticides registered

with the US EPA were considered. Therodenticides were dismissed for one or more ofthe following reasons: 1) lack of proveneffectiveness in island rat eradications; 2)potential for development of bait shyness in therat population; 3) inability to cope with thepotential “Warfarin resistant” rats; and 4) theunavailability of an antidote in case of humanexposure. Each of these issues and theassociated rodenticides are discussed below. For


CHAPTER TWO - 27

a summary of the registered rodenticidesconsidered, see Table 2.

Previous island wide eradication projects (forislands greater than 10 ha) have only utilizedbrodifacoum, bromadiolone, and warfarin (Table2). Bromethalin was used in conjunction withbrodifacoum on one island. None of the otherrodenticides have been used for islanderadications.

The use of bromethalin and zinc phosphideif used extensively, could result in thedevelopment of “bait shyness”. Bait shynessdevelops in a rat population when symptoms ofexposure are associated with the bait presentedsuch as bromethalin and zinc phosphide. Studieshave demonstrated that even with pre-baiting,only 60- 70% of rats would be controlled withan acute rodenticide (Lund 1988). Anyindividual rat that survives a round of exposureis likely to avoid the bait in the future (Recordand Marsh 1988). If rats were to survive abaiting application on Anacapa Island, the effortrequired to remove those individuals would begreater than if a non-acute rodenticide whichdoes not induce bait shyness was used.Cholecalciferol may also lead to “bait aversion”because of the high concentrations in the finalbait formulations (Prescott et al. 1992 inKaukeinen et al. 2000)

An attempt to control and/or eradicate ratsfrom Anacapa Island was carried out over anumber of years in the 1980s and early 1990s.Many control methods were attempted includingdelivery of Warfarin via bait stations. Thecontrol of rats can be a strong selection agent,increasing the frequency of rats that cannot bekilled via the control method used. Wherepopulations of rats have been previouslyexposed to poison, some rats demonstrate baitavoidance behavior and others may bebiochemically “resistant” to the anticoagulantused.

It is unknown if the population of rats onAnacapa Island contain individuals that woulddemonstrate bait shyness or are “Warfarin-resistant”. If rats are resistant to Warfarin, theamount of bait used would require greater andgreater amounts of warfarin to induce a toxiceffect. It may be that “Warfarin resistant”individuals are insensitive to the other firstgeneration anticoagulants such as diphacinoneand chlorophacinone (Greaves 1994). Even ifwarfarin resistance is not present in a ratpopulation, the use of first generationanticoagulants may not induce 100% mortalityof the target species under standard EPAlaboratory efficacy studies.

The use of rodenticides in the field does posesome degree of risk, albeit small (due to the factthat humans would have to intentionally ingestthe bait, in large quantities to do harm), tohumans on the islands. On Anacapa Island, baitwould be applied to East Island, which visitorsfrequent, so there is some potential for visitors tobe exposed to any rodenticide. However, theexposure to human visitors is extremely low.All of the rodenticides represent a risk ofexposure. However, most have an antidote(Vitamin K1 for the anticoagulants, andcalcitonin for cholecalciferol) which counteractthe activity of the rodenticide. Of the acuterodenticides, symptoms would be measurablesoon after ingestion. If sufficient quantitieswere consumed, immediate intervention wouldbe required including medical evacuation. Amajor disadvantage of the acute rodenticides,from a human health perspective, is the lack ofan antidote.


CHAPTER TWO - 28

TrappingThis alternative would have used live traps

and/or kill (snap) traps to eradicate rats fromAnacapa Island. This alternative was dismissedbecause it failed to meet the purpose and needand is technologically infeasible.

The use of live traps and/or kill traps toremove rats from an area is a strong selectionagent and selects for rats that are “trap shy”.Thus, the frequency with which rats are trapped

decreases with the increasing effort of trapplacement. Therefore, a prohibitive financialand time investment would be required to trapthe few remaining rats from Anacapa Island.This technique has not been successfully used onother islands and likely would result in a largecontrol program that, in effect, would harvest thesurplus rats.

The implementation of a trapping regime onAnacapa Island would require substantial laborand subsequent financial investment. Traps

Table 2. Characteristics of rodenticides registered with the US EPA

Rodenticide Category

PreviousSuccess in

IslandRestoration

ActivityAbility to

Induce BaitAvoidancea

Danger toHumans

AntidoteAvailable?

BrodifacoumSecond

GenerationAnticoagulant

High Single Feed Very Low Low Yes

DifethialoneSecond


No Data Single Feed Very Low Low Yes

BromadioloneSecond


Low Single Feed Very Low Low Yes

ChlorophacinoneFirst


No Data Multi-Feed Low Low Yes

DiphacinoneFirst


No Data Multi-Feed Low Low Yes

WarfarinFirst


Low Multi-Feed Low Low Yes

Bromethalin Subacute Low Single Feed High High No

Cholecalciferol Subacute No Data Single Feed Possible Moderate Yes

Zinc Phosphide Acute No Data Single Feed High High No

a See text for definition


CHAPTER TWO - 29

would have to be laid on the cliffsides andshoreline of the island to be successful. Staffservicing traps would be placed at risk ofencountering numerous vector bone diseasesfrom handling rodents and used traps. Theeffects of personnel scaling the cliffs has beendiscussed in the first alternative considered butdismissed (see above). There is also the highprobability of capturing non-target species suchas landbirds, seabirds and mice in the traps.Therefore, this alternative is infeasible toimplement.

Introducing PredatorsThis alternative is one form of biological

control that was recommended during thescoping period. The introduction of predatorssuch as snakes and cats was recommended;however, this was dismissed because it fails tomeet the purpose and need. It also would resultin unreasonable damage to the environment, anddoes not conform to the Park’s GeneralManagement Plan.

The introduction of cats to islands in order tocontrol introduced rats has been attemptednumerous times since European explorers begancrossing the Atlantic and Pacific Oceans insearch of riches. The introduction of a predatorsuch as cats to control rats usually results in agreater impact on birds than if one or the otherwere present alone. When seabirds are present,cats have been demonstrated to prey heavily onseabirds (Keitt 1998, Atkinson 1985) takingfewer rats. When the seabirds leave the island,the cats turn to rats which artificially maintainthe population at a higher level than if the ratswere not present (Atkinson 1985). Thus, birdsare impacted by both rats and the larger numberof cats present due to the rats. Introduction ofanother species into an island ecosystem canhave severe and permanent consequences (seeQuammen 1996). The introduction of non-native species has been identified as the leading

cause of species extinctions on islands (Tershyet al. 1997).

Summary of Alternatives

A summary of the major features of eachalternative can be found in Table 3. Theenvironmental impacts of implementing eachalternative are discussed in Chapter Four. Thealternatives differ in their approach todistribution of a rodenticide (aerial, bait station)across the island and the active ingredients usedin the rodent bait.


CHAPTER TWO - 30

Table 3. Summary of Alternatives for the Anacapa Island Restoration Project.

East Anacapa Middle Anacapa West AnacapaAlternative

Top Cliff Top Cliff Top Cliff

ActiveIngredient

Concentration(ppm)

1 (No Action) NA NA NA NA NA NA NA NA

2 (Preferred) Aerial Aerial Aerial Aerial Aerial Aerial Brodifacoum 25


Stn Aerial Aerial Aerial Brodifacoum 25

4 Aerial Aerial Aerial Aerial Aerial Aerial Bromadiolone 50


Stn Aerial Aerial Aerial Bromadiolone 50

6 Aerial Aerial Aerial Aerial Aerial AerialDiphacinone

andBrodifacoum

50and25


CHAPTER THREE - 31

........


CHAPTER THREEAFFECTED ENVIRONMENT

Chapter Contents

INTRODUCTION ........................................................................................................................ 32

PHYSICAL ENVIRONMENT..................................................................................................... 32SETTING................................................................................................................................................ 32GEOLOGY.............................................................................................................................................. 32SOILS..................................................................................................................................................... 34CLIMATE ............................................................................................................................................... 34AIR QUALITY (CLEAN AIR ACT)......................................................................................................... 35

TERRESTRIAL ENVIRONMENT.............................................................................................. 36INVERTEBRATES ................................................................................................................................... 36HERPETOFAUNA.................................................................................................................................... 37AVIAN................................................................................................................................................... 38

Landbirds ....................................................................................................................................... 38Seabirds ......................................................................................................................................... 38

MAMMALS ............................................................................................................................................ 41

RARE, THREATENED AND ENDANGERED PLANTS......................................................................... 41

MARINE ENVIRONMENT ........................................................................................................ 42MARINE MAMMALS.............................................................................................................................. 42

California Sea Lion........................................................................................................................ 42Harbor Seal.................................................................................................................................... 42

MARINE INVERTEBRATES ..................................................................................................................... 44

HUMAN USES AND VALUES ................................................................................................. .45


CHAPTER THREE - 32

IntroductionThis chapter focuses on portions of the

environment that are directly related toconditions addressed in the alternatives. Thedescription of the affected environment isnot meant to be a complete description ofthe project area. Rather, it is intended toportray the significant conditions and trendsof the resources that may be affected by theproposed project or its alternatives.Information in this chapter is basedprimarily on the Natural Resources Studyconducted in 1979 by the Santa BarbaraMuseum of Natural History, inventory andmonitoring data from the Park’s resourcemanagement staff, independent researchstudies, and studies conducted as part of thisproposed action. Other sources are notedwhere applicable.

This chapter is organized into foursections, which when taken together providethe most complete description of the islandresources, including the human element.The four major components of this chapterare:

� Physical Environment

� Marine Environment

� Terrestrial Environment

� Human Uses and Values.

For the most part, geologic andclimatological conditions, processes, anddisturbances cannot be altered bymanagement activities. Watershed, soil, andatmosphere conditions and processes, alsopart of the physiographic setting, can bemodified by certain management activities.However, the management activities that areproposed in this analysis would not affectthe physiographic settings.

Physical Environment

SettingOff the coast of Southern California,

eight ridges in the continental shelf riseabove sea level, forming a series of islands.The four northern islands are located in theSanta Barbara Channel parallel to the coastsouth of Point Conception: the four southernislands are scattered offshore between LosAngeles and the Mexican border.

The Channel Islands vary greatly in size,distance from each other, and distance tofrom the mainland, creating an immensenatural laboratory of isolation and evolution.Because the islands have escaped much ofthe historical human impact on coastalCalifornia, they provide an ideal place for aNational Park.

Of all the Channel Islands, the smallestand closest to the mainland is AnacapaIsland. Totaling 296 ha, Anacapa Islandwith its three islets (East, Middle, and West)is just over 1 square mile in area. One of thenorthern Channel Islands, it lies southwestof the City of Ventura, 9 miles across theSanta Barbara Channel from the nearestmainland point.

Geology(Adapted from Gustafson, 1999) The

Channel Islands are but exposed peaks in atopographically complex area of submarinebasins and ridges known as the ContinentalBorderland. This has been a region ofintense geological activity – includingcrustal deformation, volcanism, faulting,uplift, and erosion – caused by local tectonicprocesses.


CHAPTER THREE - 33

The deep wrinkles of today’s Boderlandbegan to form in a previously broadcontinental shelf during the Oligocene epoch(30 million years ago) in response to stressat the boundary of the North American andoceanic plates. Widespread volcanicactivity both on and off shore followed inthe Miocene epoch (24 to 7 million yearsago), as the Farallon Plate was subductedunder the continental shelf.

Among the ranges created by thistectonic activity was the Santa MonicaMountains Range, which originally rannorth and south. By the end of the Miocene,however, this range had rotated into itspresent east-to-west orientation, as hadseveral other mountain chains now knowncollectively as the Transverse Ranges. Thefour northern Channel Islands, includingAnacapa Island, constitute the seawardextension of the Santa Monica Mountains,which rise in downtown Los Angeles,plunge into the ocean at Point Mugu, andcontinue westward for many miles.

During the Pleistocene ice ages, sealevels dropped enough for the four northernislands to form a single, vast island nowknown as Santarosae. For decades, scientistassumed that a landbridge once connectedSantarosae to the mainland range as well.But as bathymetric knowledge of the oceanfloor improved, geologists concluded thateven during periods of lowest sea levels(about 17 thousand years ago), theconnection between the mainland andSantarosae remained submerged. Asglaciers melted at the close of thePleistocene, rising sea levels flooded lowerelevations of Santarosae, leaving the higherregions exposed and separated.

Anacapa Island is mostly made up ofvolcanics, miocene basalts, andesites, and

breccias formed largely by underwatereruptions 15-20 million years ago.

Geologic reconnaissance conducted byJohnson (1979) on Anacapa Island describedthe bedrock geology, quaternary marineterraces and sediments, and quaternaryterrestrial sediments.

Bedrock GeologyThe bedrock geology of Anacapa Island

is comprised of dark colored Miocene Conejovolcanics with some modest to significantinterbeds of lighter-colored San OnofreBreccia, also of Miocene age. Some of thebasalt is of the pillow type indicatingsubmarine eruptions. Various joints, faults,and fractures are seen in the sea cliffs aboutthe island and where these intersect the sea,sea caves have formed. Scholl (1960)concluded that Anacapa has tilted to thenorthward as a unit in the Late Pleistocene orHolocene. This tilt is very apparent on eachof the three islets.

Quaternary Marine Terraces andSediments

Quaternary marine terraces and sedimentsoccur at various elevations, the mostconspicuous of which is the 250-ft. terracewhich dominates the mesa-like form ofMiddle and East Islets. These have beendescribed by several authors (Scholl 1960;Lipps 1964), and occur at 25 and 250 feetelevations. During the geologicalreconnaissance associated with the presentstudy, beach deposits were found at 25, 250,650, 800, and 840 ft.

Marine sediments occur on all three isletsbut have been preserved best on Middle andWest Islets. On Middle Islet, however,fosssiliferous terrace deposits occur at 25-ft.


CHAPTER THREE - 34

elevation, and a marine unit some 2.5 – 4.5feet thick veneers at the 250-foot terrace.

Quaternary Terrestrial SedimentQuaternary terrestrial sediments are thin

on East Islet, ranging from 0 –8 ft. thick, buton Middle and West Islets range up to 15 – 50feet thick respectively. At the boat landing atthe east-end of West Islet a terrestrial unitoccurs which has yielded many remains ofbirds, at least one of which is extinct.

SoilsSoil information on Anacapa Island is

known from a reconnaissance surveyconducted by Johnson (1979). From eighthand-dug pits and soil lab analysis it wasdetermined that the Island has three majorsoil types.

Lithic Xerorthents – soils found onmoderately steep to steep recent erosionalslopes.

Typic Chromoxererts – clayey, poorlyhorizonated soils that shrink and crackduring summers and swell when wettedduring winters. Found on gentle tomoderate slopes on all three islets.

Vertic Argixerolls – clayey, organic matter-rich soils that have shrink-swellcharacteristics such that it forms significantcracks in summer. Found on the gentlestand flattest portions on all three islets.

Status and TrendDetermination of the status or trend of soilresource conditions for Anacapa Island isdifficult because of the lack of monitoringdata. Generally, declines in soil quality andproductivity are associated with intensivevegetation management activities, roading,

and grazing. Prior to becoming a NationalMonument in 1938, all three islets had beengrazed primarily by sheep. East Islet hadsheep grazing between 1902-1912, andMiddle and West Islets were grazed from1902-1937 (Johnson 1979). It is estimatedthat soil resources were significantlyaffected during this period, but has sincerecovered. However, to varying extents theislets have been invaded by alien grass andforb species. The impacts to soil resourcesas a result of these invasive species are notknown.

Cyanobacterial crustsCyanobacterial crusts are important for

increased soil stability, water infiltration,and fertility of soils. Cyanobacterial crustsare common on the Channel Islands.Surveys done by Belnap (1994) indicate thatcyanobacterial crusts should cover the soilsurfaces in most of the vegetation typesfound in the Channel Islands.

These soil crusts are impacted by soilsurface disturbance, including grazing,people and off-road vehicles. The onlyopportunity currently for these crusts to bedisturbed on Anacapa Island is throughtrampling by people.

Although restricted to hiking trails onEast Anacapa Islet, authorized activitiessuch as iceplant removal and terrestrialanimal monitoring, as well as unauthorizedtrampling by errant hikers may impact thesecrusts. Middle and West Islets receiveminimal foot traffic.

ClimatePrecipitation and Temperature

The Channel Islands enjoy theMediterranean climate typical of the central


CHAPTER THREE - 35

California coast. Rain pelts the islands offand on from November to March, but isscarce from late May to October, when astable Pacific high-pressure system settlesoff the coast. A shallow coastal marinelayer helps ameliorate summer droughtconditions on the islands in all but the driestof years.

Northwesterly winds blow throughoutthe year, picking up speed most afternoonsand dropping off at night. These windsdrive fog against the islands’ northwesternslopes, which provide very different climatic

conditions than the south-facing coastalslopes of the mainland. Santa Ana windsoccasionally disrupt this pattern, particularlyin the fall and early winter. These hot drywinds blow from the east when high-pressure systems are present of the interiormainland.

DroughtDrought is an important process that affectsecosystems. Drought is defined as anabsence of usual precipitation (less than 75percent of normal), for a long enough period

that there is decreased soil moisture andstream flow, thereby affecting ecologicalprocesses and human activities. Droughtconditions occur frequently on AnacapaIsland.

Air Quality (Clean Air Act)Current Status and TrendThe history of air quality monitoring on theChannel Islands goes back to the period of1988-1992 when a air quality station waslocated on East Anacapa Island. This station

monitored ozone, sulfur dioxide,hydrocarbons, and nitrogen oxides. Thisstation was removed when the Coast Guardconverted the Anacapa lighthouse to solarpower, and removed the power supply forthe air quality station. In 1996, incooperation with the Santa Barbara CountyAir Pollution Control District, an ozonemonitoring station was built on Santa RosaIsland.

It is probable that the combination ofprevailing wind patterns, a low natural firehistory, and small human populations has

Table 4. Anacapa Island-Lighthouse 1992 Ozone Summary (Ventura County Air Pollution Control District)

Number of Days StandardExceeded

1-hr OzoneConcentrations

ppm

8-hr OzoneConcentrations

ppmYear

% ofDays

Moni-tored State 1-

hourFederal 1-

hourFederal 8-

hour**1st

High2nd

High3rd

High4th

High EPDC* 1stHigh

2ndHigh

3rdHigh

1992 67% 4 0 2 0.100 0.100 0.100 0.100 0.102 0.094 0.090 0.081*The Expected Peak Day Concentration (EPDC) is calculated based on data for 3 successive years, listed by the last

year of the three year period. The EPDC represents the ozone concentration expected to occur once per year.**Proposed Federal Standard


CHAPTER THREE - 36

allowed for generally good air quality on theisland. Following the population anddevelopment boom along coastal southernCalifornia, however, poor air quality iswidespread, and smog often mars thevisibility from and around the islands.

The phenomenon of "Santa Ana" windsthat come from a northeasterly, inlanddirection can greatly affect air quality atAnacapa Island. These winds usually occurduring fall and winter and arecharacteristically warm and dry and may be ofvery high velocity near the mainland shore.They primarily affect those islands close tothe mainland by carrying out to sea the airpollution usually found onshore. Satelliteimages show that Santa Ana winds can carrypollutants several hundred miles offshore andhave the potential to negatively affect all ofthe park islands. A bigger concern relative toair pollutants in the Channel Islands is a"Catalina eddy" that can bring pollutants upthe coast from the Los Angeles basin and apost-Santa Ana event where the air pollutantsthat were pushed offshore come slowly backto the coast. Another type of pattern thatwould bring moderate levels of air pollutantsto the Channel Islands is an eastern Pacifichigh pressure system that causes light windsand poorly dispersed air. Normally, the seabreeze pushes the air pollutants to the coastand keeps low levels of air pollutants in theChannel Islands.

Terrestrial Environment

IntroductionThis section provides a description of

the terrestrial component of Anacapa Islandthat is directly related to conditionsaddressed in the alternatives. As such, it is

not a complete description of the entireterrestrial environment. This chapter isorganized to focus on the sub-issuesidentified for the terrestrial environmentusing the best information available. Thischapter will also include descriptions of thesignificant conditions and trends of theresources that may be affected by theproposed project or its alternatives. Listedbelow are the four terrestrial componentsthat will be described in this section:

� Invertebrates� Herpetofauna� Avian� Mammals

InvertebratesCurrent Status

A natural resources study completed bythe Santa Barbara Museum of NaturalHistory (Miller and Hochberg 1979)generally described the dominant insects onAnacapa Island. The survey focused oninsects that would have been of specialinterest to the Park such as, endemics andpests. Since that time, several studies haveadded to the knowledge base of invertebratespecies for Anacapa Island. In the ParksTerrestrial Invertebrate MonitoringHandbook (Fellers 1991), the Park providedan update of invertebrate fauna that wasknown to exist on Anacapa Island. Table 5shows a comparison of the species identifiedin 1979 by Hochberg and Miller (1979) andthe current state of knowledge. Table 6describes the number and proportion ofendemic terrestrial invertebrate taxa onAnacapa Island.

The Parks report (1989) states thatdespite the increasing knowledge of thecomposition of the terrestrial invertebratefauna, there is still an almost complete lackof data on the ecology, distribution and


CHAPTER THREE - 37

abundance of invertebrates on the parkislands.

Trend Channel Islands National Park developed aTerrestrial Invertebrate MonitoringHandbook (Fellers and Drost 1991) for thepurpose of detecting significant changes inthe diversity, abundance and distribution ofterrestrial invertebrates. Because of theisolation of the Islands, the Park isespecially interested in expansion of non-native invertebrates into native plantcommunities. Unfortunately, due tobudgetary and personnel constraints themonitoring program has not beenimplemented. As a result, trend estimatesfor the invertebrate population’s “health” onAnacapa Island is not known.

HerpetofaunaCurrent StatusHerpetofauna for this discussion includesnative amphibians and reptiles on AnacapaIsland. Only one native amphibian, thePacific Slender Salamander (Batrachosepspacificus pacificus) and two native lizards,the Side-blotched Lizard (Uta stansburiana)and the Southern Alligator Lizard (Elgariamulticarinatus), occur on Anacapa Island.

In 1988 the Park published a protocol(Fellers et. al. 1988) for monitoringterrestrial vertebrates within the Park. Asignificant portion of the monitoringprotocol was directed at monitoring thePark’s amphibians and reptiles. Thepurpose of monitoring was to determinepopulation status. Population status wasreported using two parameters; 1) anuncalibrated index of population size and, 2)weight-length regression. The populationindex allows the park to track changes inpopulation size and thus detect both long-term trends and sudden, short-term changes.The weight-length regression provides ameasure of the general health of thepopulation.

Trend:Data collection on the reptiles and

amphibian monitoring began in 1993.Figure 2 shows the population index forboth species.

Normal year-to-year changes can beexpected for the salamander because theiractivities are strongly moderated by rainfall.As shown in Figure 2 the population indexfor the pacific salamander increaseddramatically during the wet winter season of1997-98.

Table 5. Terrestrial Invertebrates known fromAnacapa in 1979 (Hochberg 1979; Miller 1979)and 1989.

Taxa 1979 1989

Snails 2 2Insects 94 130Other Arthropods 3 7Total 99 139

Table 6. Number and proportion of endemic taxaon Anacapa Island (Fellers and Drost 1991).

Taxa No. ofSpecies

TotalEndemic(percent)

Snails 2 1(50)

Arthropods 137 18(13)


CHAPTER THREE - 38

AvianLandbirdsCurrent Status

Twenty-two species of landbirds areknown to breed on Anacapa Island(Diamond and Jones 1980). Seven of thesetaxa are recognized as endemic subspecies,occurring only on Anacapa and one or moreof the other Channel Islands (Johnson 1972).TheseendemicspeciesincludetheAllen’sHummingbird(Selasphorussasinsedentarius),Pacific-slopeFlycatcher(Empidonax difficilis insulicola), Horned Lark(Eremophila alpestris insularis), Bewick’sWren (Thryomanes bewickii newophilus),Loggerhead Shrike (Lanius ludovicianusanthonyi), Orange-crowned Warbler(Vermivora celata sordida), House Finch(Carpodacus mexicanus frontalis) andRufous-crowned Sparrow (Aimophilaruficeps obscura).

Not all of the species that are known tobreed on Anacapa Island were observedduring the 1995-1997 National Park Servicesurveys. Middle and West Anacapa Island

were not included in the transects and couldhave contained breeding landbirds (Austinand Coonan 1998). West Anacapa Isletprovides the best landbird habitat out of thethree Anacapa islets, due to its greatertopography and more extensive stands ofnative shrub vegetation, including coastalsage scrub and coreopsis scrub. A completelist of landbirds found on Anacapa Islandcan be found in the Appendix.

Trend:Part of the

terrestrialmonitoringprogram atChannelIslands isfocused onmonitoringlandbirds. Theobjective of themonitoringprogram is toprovide, on anannual basis,species andnumbers ofbreeding land

birds on Park Islands. Counts are made toprovide information on relative abundanceof all breeding birds on each island duringbreeding and non-breeding periods eachyear.

SeabirdsCurrent Status

Currently there are eight species ofnesting seabirds on Anacapa Island. Of theeight species, three are classified as beingSpecies of Special Concern in California.These Species of Special Concern include

Figure 3. East Anacapa Island Fall Landbird Counts

0

10

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30

40

50

60

70

1993 1994 1996 1997

Num

ber

Bewick's Wren Black Phoebe European StarlingHouse Finch House Wren Orange-crowned WarblerRock Wren Red-tailed Hawk Say's PhoebeSavannah Sparrow White-crowned Sparrow Western MeadowlarkYellow-rumped Warbler


CHAPTER THREE - 39

the Ashy Storm-Petrel (Oceanodromahomochroa), Double-crested Cormorant(Phalacrocorax auritus), and the Xantus’Murrelet (Synthilboramphus hypoleuca)(California Department of Fish and Game1992). The Xantus’ Murrelet is also listedas a Federal Species of Concern (U.S. Fishand Wildlife Service 1998). The ChannelIslands National Park also provides onehundred percent of the state’s population ofnesting Xantus’ Murrelet. Figure 4 showsthe critical seabird areas on Anacapa Island.

One of the breeding seabirds onAnacapa Island is the California BrownPelican (Pelecanus occidentaliscalifornicus), which is listed as a federalEndangered species. One hundred percentof the state’s population of nestingCalifornia Brown Pelican occurs onAnacapa and Santa Barbara Island. Becauseof its significance as a listed species underthe Endangered Species Act, the Park will

be consulting with the U.S. Fish andWildlife Service on this project.

Factors that threaten nesting seabirds onAnacapa Island include predation byintroduced Black Rats (Rattus rattus), oilpollution, organochlorines, and gill nets(Drost and Lewis 1995). The introductionof non-native plant species may play a rolein loss of habitat, but the numbers of nestingseabirds on Anacapa Island are stillrelatively low compared to the availablehabitat.

Trend Brown Pelican

In the 1950’s the pesticide DDT heavilyimpacted Brown Pelicans. The pesticidewas concentrated as it moved up the foodchain and in Pelicans and other predatorybirds caused the eggshells to be so thin thatthe incubating adult crushed the eggs. By

Figure 4. Critical Seabird Areas.


CHAPTER THREE - 40

1968 the population was so low that only100 pairs bred on Anacapa Island and onlyfour chicks fledged. For this reason, BrownPelicans were listed as a FederallyEndangered Species. DDT was banned inthe U.S. in 1972 and since then BrownPelican numbers have increased. Todaythey are close to, or above historicalpopulation sizes, making the Brown Pelicana conservation success story.

Today Brown Pelicans are susceptible topollution (especially oil spills and fishinggear entanglement), disturbance, andpredation of eggs and young chicks byintroduced species.

Brown Pelicans are particularlysusceptible to disturbance in the early part ofthe breeding season; during incubation andthe first three weeks of chick rearing.During this period, if adults are disturbedthey will fly off the nest leaving the eggs oryoung chicks exposed to heat, cold, or gulland raven predation. For this reason,breeding colonies such as Anacapa Islandmust be strictly protected during thebreeding season. Even a single group ofvisitors during the breeding season canresult in complete breeding failure overlarge parts of the colony.

During the non-breeding season BrownPelicans are much less susceptible todisturbance. They will fly off if approachedclosely, but the only impact this has onindividuals is the energetic cost of flyingaway and the time lost flying that could beused for preening or resting. In addition,adults are much less likely to beenergetically stressed during the non-breeding season when they are non-involvedin courtship or chick rearing. Consequently,during the non-breeding season, singledisturbance events will have little impact on

Brown Pelican populations. However,repeated disturbance of non-breeding BrownPelicans could have a cumulative impact if itcaused a significant energetic drain orsignificantly reduced time available forpreening.

Species of Special Concern Two of the species of concern are sea

cave/crevice nesting seabirds that aresusceptible to disturbance. These speciesAshy Storm-Petrel (Oceandodromahomochroa) and Xantus’ Murrelet(Synthliboramphus hypoleucus) nest insimilar habitats on Anacapa Island.Population decline in both species has beendocumented by Sydeman et al. (1998).

The executive committee of the PacificSeabird Group has authorized a committeeto draft a petition to list the Xantus’Murrelet for protection under theEndangered Species Act. The PacificSeabird Group, however, has yet to renderan opinion on the merits or reasons forlisting Xantus’ Murrelet.

In addition to rat impacts on the murrelet,other disturbance factors such as oil pollutionand the associated impacts (increasedpredation, disorientation, disruption) frombright lights from squid boats who fishadjacent to Anacapa Island may becontributing factors to the decline of theXantus’ Murrelet population.

An assessment of nesting habitatconfirmed the impacts of introducedpredators on the Xantus’ Murrelet onAnacapa Island. Of the estimated 505potential nesting sites accessible to rats, onlytwo sites, or 0.4%, had evidence of nestingmurrelets (McChesney et al. 2000). Botheggs showed evidence of mammalianpredation and were in areas where rats


CHAPTER THREE - 41

Figure 5: Mean Deer Mice Densities (No/ha) Anacapa Island.

0

50

100

150

200

250

300

93 94 95 96 97 98 99 GrandTotalYear

Num

ber/h

a

Fall Spring

Mean Across All Years

appeared to be common. In contrast, on rat-free Santa Barbara Island similar surveys in1991 found murrelet eggshells in 29.4% ofpotential sites. Murrelets on AnacapaIsland are mostly limited to nesting in areasinaccessible to rats or where rats occurinfrequently.

MammalsCurrent Status

The Deer Mice on Anacapa(Peromyscus maniculatus anacapae) andSanta Barbara Islands (Peromyscusmaniculatus elusus) are the largest nativeland mammal. Both subspecies are endemicand restricted to their respective island. Asabundant generalist granivores/predators,they undoubtedly have significant influenceon the plants and terrestrial invertebrates onthe islands, as prey species, they largelydetermine the numbers of some of theresident hawks and owls (Fellers et al.1988).

As part of its vertebrate monitoringprogram, the Park has been monitoringmouse populations on Anacapa since thespring of 1993. Monitoring of Deer Miceemploys mark-recapture grids (Fellers et al.1988). There are currently 3 grids set up onAnacapa Island, one on each islet. The gridsare monitored in the spring and latesummer/fall of each year.

TrendMouse trapping has been conducted on

Santa Barbara Island since the early 1980’s.One of the most significant findings fromthis data is that there are large fluctuations inpopulation levels that are related to annualrainfall, predation pressure, and season(Fellers et al. 1988). C. Drost and others,

have hypothesized that breeding suppressionis the ultimate factor limiting the DeerMouse population on Santa Barbara Island.(This fluctuation has resulted in densitiesfrom less than 10 mice/ha to over 450mice/ha. Summarized in Figure 5 are themouse densities from Anacapa Island since1993.

Rare, Threatened andEndangered Plants

Current StatusThere is only one federally endangered

plant on Anacapa Island: IslandMalacothrix (Malacothrix squalida). Itoccurs only on Santa Cruz Island andMiddle Anacapa. On Middle Anacapa it isfound in two locations: near the Knife’sEdge and on an east facing slope near thewest end of the island.

It is an annual herb from the asterfamily. It ocurs on rocky coastal bluffs incoastal scrub.


CHAPTER THREE - 42

TrendIsland Malacothrix has been

documented from Middle Anacapa Island ontwo occasions: when it was first collected in1963 and again by Steve Junak in 1998.Local populations of Island Malacothrix onAnacapa Island are impacted by soil, habitatalteration, and localized impacts fromseabird nesting. Its limited occurrencemakes it highly susceptible to stochasticevents which could lead to extirpation fromAnacapa Island.

Marine Environment

Marine MammalsTwo species of marine mammals

utilize habitat areas on or around the shoresof Anacapa Island. These species, theCalifornia Sea Lion (Zalophuscalifornianus) and the Harbor Seal (Phocavitulina), are year round residents. Bothspecies are abundant and widely distributedthroughout the area.

California Sea LionCurrent StatusCalifornia Sea Lions are the mostconspicuous and abundant pinnipeds in thecoastal waters of southern California. Theprincipal breeding rookeries in the ChannelIslands are on the western end of SanMiguel Island, including Castle Rock, theoffshore sides of San Clemente and SanNicolas Islands, and around Santa BarbaraIsland. They haul out on all of the southernCalifornia Islands (Bartholomew et al 1970).

On Anacapa Island California Sea Lionsare known to haul out, in varying numbers,

at two locations. These locations are bothon south shore of the East Islet. Althoughpupping has been observed in these twoareas, overall habitat quality is limited dueto the marginal beaches on Anacapa (narrowand rocky and can be completely submergedduring high tide), and heavy visitation (on-shore and off-shore).

California Sea Lions are opportunisticfeeders, and feed in large groups whenschooling fish or squid are available andprobably disband when the food source isscattered (Bonnel et al. 1979). Fecesanalysis of California Sea Lions from SanMiguel Island showed squid, Pacific Hake,rockfish, and a variety of other schoolingpelagic and demersal fishes (benthic fishes)to be utilized (Antonelis et al. 1978).

Incidental set and drift gillnet fishingcontinues to be the leading human causedmortality factor. However, for the first three-quarters of 1994, when compared to the years1991-93, incidental gillnet kills showed alarge reduction (Barlow et al. 1995).

TrendSpecific population trends for Anacapa

Island is not known. However, populationtrends for four southern California rookeries,which includes rookeries from the ChannelIslands, were estimated by Barlow et al.(1995). With the exception of the El Ninoevents of 1983 and 1992, pup countsincreased at an annual rate of 5.2% between1975 and 1994. Pup counts between the ElNino events increased at 8.8% between 1976and 1982 and at 8.2 % between 1983 and1994 (Barlow et al. 1995).

Harbor SealCurrent Status


CHAPTER THREE - 43

Harbor seals are occasionally seen inand around harbors, such as the VenturaMarina, breakwaters and jetty. Traditionallythey seek to avoid the disturbance thatusually accompanies the activities ofhumans. They are much more wary thanany other pinnipeds of the Channel Islandsarea and can only be approached closelywith great caution (Bartholmew et al. 1970).Generally they haul out and breed only onthe most secluded beaches, rocks, and mudflats available, usually avoiding areasinhabited by other species of pinnipeds(Bigg 1969).

Harbor seals occur on inaccessible areasof the south shores of all three islets. Whilepups have been observed on southern WestIslet the role of Anacapa as a hauling andbreeding ground is unclear. Harbor sealmovement is usually confined to less than500 km from their pupping sites. Thegillnet fishery is the leading human caused

mortality factor for the Harbor Seal. Barlow(1995) notes that gillnet mortality may reachas high as 5-10% of the California HarborSeal population.

TrendPopulation size for California Harbor

Seals is estimated by counting the number ofseals ashore during the peak haul-out period(May/June) and multiplied by a correctionfactor that estimates the number of seals onland to those in the water. Harbor sealcounts have continue to increase each yearexcept during El Nino events of 1983 and1993. Annual population has beenestimated for the islands, and show a stablepopulation between 1983 through 1995(Barlow et al. 1995).

Figure 6. Marine Mammal Bioregions


CHAPTER THREE - 44

Marine InvertebratesCurrent Status

Intertidal invertebrates have beenmonitored by the Park since 1982 with thefollowing goals: 1) monitor trends inpopulation dynamics; 2) determine normallimits of variation; 3) discover abnormalconditions; 4) provide remedies formanagement problems; and 5) measure theeffects of management actions. Fifteen siteson four park islands are monitored eachspring and fall.

TrendFor the species that were monitored as

part of the intertidal monitoring surveyspercent cover did not vary more than 10%(See Figure 7). The biggest decline detectedby the monitoring program is for blackabalone. Since 1985 when over 900 blackabalone were counted across all Anacapamonitoring zones, the population declinedsignificantly with no individuals beingcounted the last two years (See Figure 8)

Figure 7. Average Percent Cover of Intertidal Zone, Anacapa Island (Across all Zones)

0

5

10

15

20

25

30

35

40

45

1981 1984 1986 1988 1990 1992 1994 1998

Year

Perc

ent C

over

Bare RockBarnacleEndocladiaRockweedMusselsMisc AlgaeMisc Animal


CHAPTER THREE - 45

Human Uses and ValuesChannel Islands National Park, and

specifically Anacapa Island are recognizedlocally, nationally, and internationally as anarea of exceptional scientific value withirreplaceable cultural resources, notablegeological and paleontological features andplant and animal communities that haveevolved in a unique manner because of theirisolation from the mainland. The waterssurrounding the islands contain one of themost diverse and productive marineecosystems in the world.

Anacapa Island and its surroundingwaters have status as both a state ofCalifornia ecological reserve (surroundingwaters to 1 nautical mile) and a federalresearch natural area. As an ecologicalreserve boating activities close to shore areprohibited along parts of West Islet for theprotection of nesting pelicans. West andMiddle Islet have status as a research naturalarea and are closed for from public use withthe exception of Frenchy’s Cove.

As an area of such diverse and importantresources, the Park attracts a wide array of

people to the islands. In addition to the16,000 annual visitors to the island, variousscientists, and Park personnel frequent theisland as well. Not included in this statisticis the number of people who recreate withprivate boats, or who conduct commercialfishing operations around the waters ofAnacapa Island. Figure 9 shows themonthly average for the years 1996-99 ofcampers and visitors who come ashore.

Park concessionaires provide most ofthe public transportation to Anacapa Island.Trips to Anacapa are scheduled almost dailythroughout the summer and at least onweekends throughout the rest of the year.The trips can last all day or half day.Visitors are only allowed on East AnacapaIsland or Frenchy’s Cove when conditionspermit.

Figure 8. Anacapa Black Abalone Counts

0

1 0 0

2 0 0

3 0 0

4 0 0

5 0 0

6 0 0

7 0 0

8 0 0

9 0 0

1 0 0 0

1985

1986

1987

1988

1989

1990

1991

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1993

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1995

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1997

1998

1999

Y e a r

Totals

Figure 9. Campers and Visitors Ashore

0

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Janua

ry

Februa

ryMarc

hApri

lMay Jun

eJul

yAug

ust

Septem

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Novem

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Decembe

r

Month

Ave

rage

# o

f Vis

itors

Average Numberof Campers (96-99)Average VisitorsAshore (96-99)


CHAPTER THREE - 46

Figure 10. Facilities and Trails.


CHAPTER FOUR - 47

........


CHAPTER FOURENVIRONMENTAL CONSEQUENCES

Chapter Contents

INTRODUCTION ...................................................................................................................................................... 48

ISSUE 1: EFFICACY ................................................................................................................................................ 48

INTRODUCTION ........................................................................................................................................................ 48THE RODENTICIDE AND TOXICOLOGICAL PROPERTIES ............................................................................................ 48COMPOSITION OF BAIT AND HOW IT IS APPLIED....................................................................................................... 50

Alternative 1: No Action Alternative.................................................................................................................. 50Alternatives 3 and 5: Aerial- Bait Station Combination .................................................................................... 50Alternatives 2, 4 and 6: Aerial Broadcast.......................................................................................................... 51

LOCAL FACTORS...................................................................................................................................................... 51SUMMARY................................................................................................................................................................ 52

ISSUE 2: NON-TARGET IMPACTS ....................................................................................................................... 52

INTRODUCTION ........................................................................................................................................................ 52PHYSICAL IMPACTS.................................................................................................................................................. 52TOXICOLOGICAL IMPACTS ....................................................................................................................................... 57RELATIVE COMPARISON OF TOXICOLOGICAL IMPACTS BY ALTERNATIVE............................................................... 58

Alternative 1 – No Action.................................................................................................................................... 58Features Common to Alternatives 2, 3, 4, 5 and 6.............................................................................................. 58

Primary Exposure........................................................................................................................................ 58Secondary Exposure.................................................................................................................................... 61

Toxicological Impacts by Sub-Issue.................................................................................................................... 64Sub-Issue 1: Marine Mammals .........................................................................................................................................64Sub-Issue 2 – Invertebrates ................................................................................................................................................66Sub-Issue 3 – Fishes...........................................................................................................................................................66Sub-Issue 4 – Herpetofauna ...............................................................................................................................................67Sub-Issue 5 and 6 – Seabirds and Landbirds......................................................................................................................69Sub-Issue 7 – Terrestrial Mammals....................................................................................................................................74

CUMULATIVE EFFECTS ............................................................................................................................................ 74

ISSUE 3: PUBLIC SAFETY AND VISITATION ..................................................................................................... 78

EXPOSURE TO THE RODENTICIDE ............................................................................................................................. 78IMPACTS TO VISITOR ENJOYMENT ........................................................................................................................... 80

SUSTAINABILITY AND LONG TERM MANAGEMENT .................................................................................... 81

ANAC AP A ISLAND RES TOR AT ION PRO JEC TFIN AL ENV IRON MEN T AL IMP ACT ST AT E MEN T

CHAPTER FOUR - 48

IntroductionThis chapter discloses the environmental

consequences of implementing each alternativedescribed in Chapter Two. The environmentalconsequences, or environmental effects will becategorized in three broad areas. The threecategories of effects are direct, indirect, andcumulative. These “effect” categories will formthe basis of the effects analysis in this chapter.

Direct effects, as defined by the Council onEnvironmental Quality, are those which arecaused by the action and occur at the same timeand place. Indirect effects are those which arecaused by the action and are later in time orfarther removed in distance. Cumulative effectsare those that result from the incremental impactof the action when added to other past, present,and reasonably foreseeable future actions.Cumulative impacts can result from individuallyminor but collectively significant actions takingplace over a period of time.

The cumulative impacts analysis has beennarrowed down to two main issues, the potentialrepeated exposures of non-target species to therodenticide and the cumulative impacts to seabirdsthat utilize Anacapa Island for breeding. Thischapter forms the scientific and analytical basisfor the relative comparison of effects presentedtowards the end of Chapter 3.

Issue 1: Efficacy

IntroductionThis section of the analysis compares the

different alternatives and how well they meet thepurpose and need. The objective of this projectis to remove 100% of the rat population fromAnacapa Island. Therefore, the rodenticide of

choice, and its delivery into the ecosystem,must offer the greatest probability of achievingsuccess. The success of the eradication isdependent on the rodenticide chosen, the baitcomposition and its delivery into the ecosystemand awareness of the local conditions that couldbe exploited to maximize success. These factorswill be analyzed for each alternative.

The Rodenticide andToxicological Properties

There are three rodenticides outlined in thealternatives. They are brodifacoum,bromadiolone (second generation anticoagulant)and diphacinone (first generation anticoagulant).All of these chemicals are anticoagulantrodenticides, which cause mortality to the targetspecies through hemorrhaging (SeeBiochemistry below for further discussion). Ingeneral, the difference between the first andsecond generation anticoagulants is their acutetoxicity to rats, the amount required to kill rats,and their ability to control a population of rats.

The acute toxicity of the rodenticides arepresented in Table 7. Acute toxicity (LD50 ) isdefined as the amount of active ingredient (mg)per kg body weight, required in a single oraldose to kill 50% of a test population. Only theacute toxicity of brodifacoum is known to thetarget species, Rattus rattus. The other LD50

data presented are based on Norway rat(laboratory rat) data that may not berepresentative for Rattus rattus. Following thepattern of toxicity for the lab rat across all threeanticoagulants, brodifacoum is approximatelytwice as toxic as bromadiolone, and orders ofmagnitude more toxic than diphacinone.Although all the rodenticides are toxic to thetarget rat species, in practice, the rodenticidesdiffer in their ability to kill the target species.

The rodenticides presented are classed aseither “single feeding” or “multi-feeding”rodenticides. The first generation anticoagulantdiphacinone is a “multi-feeding” rodenticide in

ANACA PA ISLAND RES T ORAT ION PRO JECTFINAL ENVIRON MENTAL IM PA CT ST AT EM EN T

CHAPTER FOUR - 49

that rats are required to feed on the bait over aperiod of days (estimated around 7 days) tocause death. This is due to the ability of rats tometabolize and excrete the chemical in arelatively short period of time negating the toxiceffect of the initial dose. However, if the ratsfeed on the bait exclusively for a period of days,the toxic effect will take hold and cause death.Brodifacoum and bromadiolone are somewhatinsensitive to metabolism, relative todiphacinone. These compounds can cause deathafter a “single feeding” if enough of therodenticide is consumed. In other words, rats onthe island would have to only consume a smallamount of bait to cause death if brodifacoum orbromadiolone were used in sufficient

concentrations (which would still be less amountof active ingredient than if a first generationcompound were used). From an eradicationstandpoint it is necessary that every individualexposed to the rodenticide succumbs. Therefore,a bait, able to kill after ingestion a singlemouthful would be most efficient for eradicationpurposes (Eason 1991 as cited in Taylor 1993).

Variation exists within every rat populationto the susceptibility of the rodenticides. Of mostinterest in an eradication program are thoseindividuals which require more and more bait toinduce mortality, or show bait avoidancebehavior. It is those individuals that may causefailure and form the founding population in the

Table 7. Amount of bait required (g) for rats to reach one LD50.

Active Ingredient (Rodenticide)

Brodificoum 25 ppm

Alternative 2,3 and 6

Bromadiolone 50ppm

Alternatives 4,5

Diphacinone 50 ppm

Alternative 6

LD50 (mg/kg; range) 0.26-0.56 a 0.56-0.84 2.3 – 7.0

Rat Weight (g)b 150 150 150

mg Active Ingredient 0.039 - 0.084 0.084 – 0.13 0.35 – 1.05

Amount of Bait (g) 1.56 – 3.36 1.68 – 2.52 6.9 - 21

Number of Pellets 0.78 – 1.68 0.84 – 1.30 3.5 – 10.5

Number of FeedingDaysc 0.16 – 0.34 0.17 – 0.25 0.69 – 2.1

a LD50 for black rat (R. rattus) is 0.65-0.73. All LD50 data is for Norway rat (Laboratory). Comparing laboratory ratdata across the different rodenticides, bromadiolone is half as toxic as brodifacoum. If the LD50 differences betweenbrodifacoum and bromadiolone for the lab rat follow a similar pattern for the black rat, the LD50 data presented may betoo low. Conservatively, the feeding estimates should be considered an absolute minimum to one LD50.

b from Erickson (1990)c assumes approximately a 10g daily requirement of dry matter per day based on the allometric equation: FoodIngestion Rate (g/day) = 0.621(Weight)0.564 . Assumes bait is 100% Dry matter and satisfies daily requirements.


CHAPTER FOUR - 50

future, making it that much harder to removerats from the island because of the inheritedlower susceptibility. Diphacinone, with itsmulti-feeding requirement to induce mortality,increases the probability of rats surviving postapplication due to bait avoidance, inadequatebait consumption or other mechanisms. The useof brodifacoum is proposed to “clean up” thoseremaining individuals that were not lethallyexposed to the diphacinone bait. However,under alternative 6, the repeated use ofdiphacinone bait would select for individualsthat require more and more rodenticide to bekilled or show higher bait avoidance behaviordue to previous exposure to diphacinone. If ratsthat survive show bait avoidance behavior, theymay avoid the brodifacoum bait when presented.Thus, there is lesser confidence in achievingeradication under alternative 6. Bromadiolone,(alternatives 4 and 5) would increase theprobability of killing all target animals becauseof its greater toxicity and its “single-feeding”label. However, bromadiolone has been shownto be unable to control 100% of Rattus rattusafter two day’s of feeding on 50 ppm bait(Buckle 1994). After the presentation of equalconcentration of brodifacoum and bromadioloneto a study population of black rats, onlybrodifacoum killed 100% of the rats after 1 dayand 2 days of presentation. Bromadiolone wasonly effective in killing 47% and 90% after oneand two days of feeding (Buckle 1994).

Only brodifacoum offers the highestprobability of achieving the 100% kill of rats,thus, meeting the purpose and need of theAnacapa Island Restoration Project. Brodifacoumhas been the most extensively used rodenticide inisland restoration practices worldwide (AppendixC).

Composition of Bait and how itis Applied

This section investigates how thecomposition of the bait and its applicationmethod would affect the outcome of the

restoration project. The composition of the baitwould be commercial manufactured baits, eitherin pellet or block form. The applicationtechnique, either bait stations and/or aerialbroadcast, would differ in probability oferadication, primarily based on the movementof rats on the island. To successfully eradicaterats, bait must be delivered into each rat’sterritory across the island (Appendix C).

Each of the alternatives outlines the use ofdifferent rodenticides and/or methods ofdelivery. In each case, the aerial broadcastwould utilize a commercially manufacturedcompressed grain pellet. Bait stations would bearmed with commercial grade blocks ofapproximately 20 g or the 2 g compressed grainpellets. The baits would be formulated for highpalatability and acceptance by rats and would beconsumed readily by the target species.

Alternative 1: No Action AlternativeUnder the no action alternative, there would

be no use of rodenticides in the Anacapaenvironment, except for the localized baiting inbuildings on east island. With no rodenticideapplication, the rat population would not becontrolled, and the numbers of rats on the islandwould fluctuate within the annual cycle.Efficacy would effectively be 0% on Middle andWest Islands, and very small (>0%), on EastIsland where control would take place in the fewbuildings.

Alternatives 3 and 5: Aerial- BaitStation Combination

The use of bait stations on top of the islandas well as aerial broadcast of the rodenticidesonto the cliffsides was developed to minimizethe exposure of non-target species to therodenticide through direct bait consumption.Although it minimizes the primary exposurerisks to non-target species, may compromise thesuccess of the eradication because some


CHAPTER FOUR - 51

individuals possibly would not be exposed to thebait.

Habitat utilization by rats on Anacapa Islandfollows an annual cycle. Rats are most abundantalong the shoreline during the late dry season,and in very low density on the slopes and top ofthe island (Erickson 1990; Howald et al. 1997;Collins 1979). General observations havesuggested that during the wet season, the ratpopulations increase and subordinate individualsare pushed into marginal territories, such as upthe slopes and on top of the island. As the dryseason progresses and food availability on topdeclines, the abundance of rats on top declines.Rats have been found in very low density on topof the island during the late dry season, but notabsent (Howald et al. 1997; ICEG 2000). Withthe use of bait stations, some rats may not enterthe stations even though they are present in theirterritory. This neophobic behavior, common inrats (Greaves 1994), may prevent someindividuals from gaining access to bait in thestations. Bait stations deployed only on top ofthe island may allow for rats to enter therodenticide free cliffsides once the aerialapplication is complete. As most cliff/shoredwelling rats have died, the subordinate rats maymove off the top of the island down to theshoreline into preferred habitat, where theywould escape exposure to the rodenticide andmeet no resistance from territorial rats. Theseindividuals could form the founder population.To overcome this potential, stations would beleft armed for over a year before any aerialbroadcast activity. This could allow forneophobic rats to get used to the stations overtime, enter, and consume the bait and die.Alternatively, if rats refuse to enter stations, theymay continue their day to day activities and dienaturally without exposure to the rodenticide.Their offspring, if any, would emerge from theirdens with the armed stations present in theirterritory and may readily enter the stations andconsume bait. Conversely, their offspring mayhave inherited the behavior of bait station

avoidance and could escape exposure. There isno island rat eradication recorded that used acombination of broadcast and bait stations andthus, there is no precedent for this type ofoperation. Alternatives 3 and 5 offer the lowestprobability of successfully eradicating rats.

Alternatives 2, 4 and 6: AerialBroadcast

The aerial broadcast of the rodenticideacross the entire island as laid out in alternatives2, 4 and 6 increases the probability that 100% ofthe rats would be exposed to the bait. Ratswould encounter pellets during their nightlyforaging excursions and neophobic behavior,such as to bait stations, would be minimized.

Local FactorsWarfarin resistance

An attempt to control and/or eradicate ratsfrom Anacapa Island was carried out over anumber of years in the 1980s and early 1990s.Many control methods were attempted,including warfarin delivered from bait stations.The control of rats can be a strong selectionagent, increasing the frequency of rats thatcannot be killed via the control method used.Where populations of rats have been previouslyexposed to poison, some rats demonstrate baitavoidance behavior and others may bebiochemically “resistant” to the anticoagulantused (Greaves 1994). It is unknown if thepopulation of rats on Anacapa Island containindividuals that would demonstrate bait shynessor are resistant to warfarin. Thus, it isrecommended to use an active ingredient thatwould be lethal to “warfarin-resistant”individuals and is able to provide a lethal dose ina “single-feeding” in case of bait shyindividuals. Second-generation anticoagulantswould kill warfarin-resistant rats and, if insufficient concentration, would kill rats after asingle feeding, thus, dramatically increasing theprobability of successful eradication.


CHAPTER FOUR - 52

TimingRat eradication programs are most likely

to be successful if they take place during theannual population cycle when no reproduction istaking place and when rat numbers aredeclining. This insures that new-born rats wouldnot emerge from the dens after all bait has beenconsumed, and that most rats would be foodstressed and therefore more likely to consumebait. Based on the population fluctuations andbreeding season of black rats on AnacapaIslands, October through January is the bestperiod for eradication (Collins 1979, Erickson &Halvorson 1990). Each of the alternativeswould be initiated during the low point in theannual cycle.

SummaryThis analysis has demonstrated that

strictly from an efficacy standpoint, Alternative2, the preferred and proposed action (the use ofbrodifacoum aerially and hand broadcast) wouldoffer the highest probability of achievingeradication and meeting the purpose and need.

Issue 2: Non-TargetImpacts

IntroductionNon-target species, are those species that

may be negatively affected from the actions ofthe project, has been broken in to twocomponents, the physical impacts and exposureto rodenticide residues.

Physical disturbance may occur from baitingactivities, and crews walking around the island.Rodenticide exposure, for the purpose of thisanalysis, can occur through direct baitconsumption (primary exposure) andsecondarily (via carcasses containing rodenticideresidues).

Physical Impacts

IntroductionThis section will analyze the impacts from

both baiting and crews walking around theisland conducting research and monitoring onthe project. The analysis is broken down bybaiting technique within alternative - aerial orbait station. Within each category, the directand indirect impact to each sub-issue will beanalyzed.

Alternative 1: No Action AlternativeThe physical impacts of this alternative

would be negligible. Physical impacts would berestricted to normal Park activities as well asintermittent Navy and Coast Guard aerialactivity around the island.

Under this alternative, no baiting would takeplace and therefore, risk of rodenticide exposurewould be restricted to non-target species in anand around buildings where rat control withrodenticides would take place.

Rats would continue to be a majorperturbation in the Anacapa ecosystem,continuing to have detrimental impacts on smallcrevice nesting seabirds, the deer mouse,invertebrates, and plants.

The rats would continue to prevent thesmaller pelagic seabirds, such as Xantus’murrelet and ashy-storm petrel, from nestingoutside of the sea caves. Murrelets wouldcontinue to be restricted to nesting in areasinaccessible to rats, although abundant nestinghabitat is found elsewhere. Murrelets utilizeonly 0.4% of available habitat on AnacapaIsland compared with 30% on rat-free SantaBarbara Island (G. McChesney, unp. data.).Rats would continue to predate nesting seabirdsand their eggs, further leading to decliningpopulation levels of the Xantus’ murrelet. Thedeclining population may lead towardsprotection under the Endangered Species Act.


CHAPTER FOUR - 53

The endemic mouse on Anacapa Islandwould continue to be at risk of extirpation. Ratshave been implicated in the 20 year extirpationof deer mice from East Anacapa Island,rediscovered in 1997. Rats had likely preyedand outcompeted the mice which resulted inextirpation. The extirpation of mice from theislets could re-occur, and could have seriousimplications for birds of prey which rely on themice as their primary prey base.

The intertidal zone would continue to be animportant foraging area for rats. Theinvertebrates would continue to be impacted,especially the lined shore crab. The terrestrialinvertebrates would continue to be an importantpart of the rat diet. The population of terrestrialmollusks on Anacapa Island, which are veryrare, would unlikely recover.

The flora of Anacapa Island would continueto be detrimentally impacted. The rats wouldcontinue to be an important vector for dispersingseeds of iceplant, a highly invasive non-nativespecies which “chokes out “ native species. Theisland oaks and cherry trees on West Islandwould continue to have low regeneration whichcould result in complete failure of regenerationof the species. There is a possible severeeconomic impact to the National Park Servicewith trying to constantly restore native habitatdue to rodent activities.

Effects Common to Alternatives 2, 3,4, 5, and 6: Aerial Broadcast

Under each of the alternatives, a helicopterwould aerially spread a rodenticide from anunderslung hopper. The helicopter would fly25-50 m above ground at an airspeed ofapproximately 50 knots. Under each of thealternatives, bait would be aerially broadcast onthe cliffsides and all of West Island would betreated. Alternatives 2, 4 and 6 proposebroadcast of the top of Middle and East Islandsas well. Alternatives 3 and 5 would use baitstations on top of the island and the impact

associated with that will be covered in a separatesection below. The total treated area variesbetween the alternatives; however, the flightoperations may have a net impact to somespecies. To ensure even and adequate coverageof the island, a crew would circumnavigate theisland by boat spreading bait by hand in keylocations.

The project’s efforts in eradication andsubsequent potential impacts to non-targetspecies and the environment would bemonitored. Crews of varying sizes wouldregularly visit study sites and collect appropriatedata.

Sub-issue 1 – Marine MammalsDirect - Resting California Sea Lions and

Harbor Seals would likely be disturbed by thehelicopter activity and boat traffic to handbroadcast bait. It is likely that these specieswould retreat from their resting areas to theocean. The disturbance to this group is likely tobe short, restricted to three passes of thehelicopter. The seals and sea lions would likelyreturn to the haulouts shortly after thedisturbance. This type of activity is somewhatcommon with functions performed by boattraffic around the islands daily.

Monitoring activities by research crewswould not take place in the vicinity of thehaulouts and would not result in disturbance orother effects.

Indirect - The seals and sea lions would notbe subject to any indirect effects as a result ofdisturbance. The disturbance would be of shortduration, and there would be plenty of alternatehaul out areas around the islands individualscould retreat to.

Sub-issue 2 - InvertebratesNo impact to this group is expected from

helicopter or any other physical activities.


CHAPTER FOUR - 54

Monitoring on study plots and traversingalong trails would not have a significant impacton this group of animals.

Sub-issue 3 – FishesDirect - No impact is anticipated other than

minor disturbance from intermittent inflatableboat traffic. The extent of boat traffic at any onepoint along the shoreline would be veryintermittent. This would result in only minordisturbance. The fish would return to normalactivities soon after departure. Boat trafficaround the Anacapa shoreline is common andfrequent. The additional inflatable boat trafficwould not be expected to increase disturbanceoutside regular Park traffic.

Indirect - No indirect impacts would beanticipated.

Sub-Issue 4 – HerpetofaunaDirect - The impacts to the herpetofauna

would be disturbance associated with foot trafficfrom researchers. The salamander would bedormant or deep within thick vegetation duringthe proposed application period and would be atlow risk of disturbance. There would likely bedisturbance to the Side-blotched and AlligatorLizards which would be active on most regionsof the island at the time of baiting. The visitingpublic walking along trails regularly disturbsunning Side-blotched Lizards, that quicklyreturn to their spots after the disturbance haspassed.

Indirect - There would be no indirectimpacts to this group.

Sub-Issue 5 – SeabirdsPelagic Seabirds

Direct - There would be no impact to thepelagic seabirds during the baiting operation,these species would be foraging offshore.During the breeding season, these species wouldbe susceptible to disturbance from research

crews walking around the island, causingflushing from nesting areas. Few, if any, pelagicseabirds would be expected to nest on top of theisland due to predation pressure from rats.

Indirect - There would likely be no indirecteffects from short duration disturbance. Ifdisturbance was of long duration or chronic,there could be nest abandonment orsusceptibility to predation. However,disturbance is expected to be of short duration,thus likely having no indirect effect.

Roosting Seabirds

Direct - The effect on the seabirds would bein the form of disturbance. Seabirds that rooston the island would likely be flushed as thehelicopter approaches. The main species ofconcern is the endangered brown pelican. Boatactivity along the shoreline to dispense baitwould likely flush roosting seabirds.Disturbance to roosting pelicans by boat trafficaround the island has been observed on AnacapaIsland (B. Keitt, pers. comm.). Most pelicansreturn to the same roosting location 10-30minutes after disturbance (B. Keitt, pers.comm.), or would likely roost elsewhere. CoastGuard and Navy helicopter activities occurperiodically on and around East Anacapa Islandwith no detrimental impact to roosting BrownPelicans (F. Gress, pers. comm.)

Monitoring activities of research crews maydisturb roosting seabirds. However, studyprotocols have been designed such that onlyminimal activity would take place around knownroosting areas, and therefore, disturbance wouldbe minimal. Monitoring would occur during thebreeding season but no monitoring would takeplace in the vicinity of the pelican colony onWest Island. Monitoring would be conductedaround breeding Western Gulls. Disturbance isthe only direct effect expected; however, itwould be of minor significance as gulls areroutinely disturbed by visitors on East Island andnest successfully.


CHAPTER FOUR - 55

Indirect Effects - Disturbance to roostingseabirds would have a low probability of indirecteffect. The disturbance from both aerial andhand-baiting would be short and there is plentyof alternative roosting areas available on theisland.

Repeated or chronic disturbance would notbe expected under any alternative.

Sub – Issue 6 - LandbirdsDirect - The immediate effects on avian

species of helicopter use above Anacapa Islandand the bait drop would involve disturbance ofroosting species. This immediate effect wouldbe minimal as the normal response of the landbirds would be to take cover in surroundingvegetation. The stress associated with thisactivity is unlikely to be greater than that causedby certain visitor activities on the island or byhelicopter use associated with other Parkoperations made in the past or future. Thehelicopter would likely cause birds of prey toflush from roosting areas. Flushing of species isa common occurrence with visitors to EastIsland, and individuals usually return to theirroost after 10 to 30 minutes. These effects areunlikely to exceed those incurred during normalPark operations.

Falling bait pellets would unlikely have asignificant effect. The approaching helicopterwould likely cause landbirds to either leave thearea or move into areas that offer protectionsuch as thick vegetation, which in turn wouldoffer protection from falling pellets.

Indirect - During the baiting operation,indirect effects would not be expected and areinsignificant. Nesting landbirds could bedisturbed during research and monitoring. Nochronic activity would be expected.

Sub - Issue 7 - Terrestrial MammalsDirect - No impact to the deer mouse is

expected. The deer mouse is primarily nocturnal

and would be in their burrows during the aerialapplication of the bait in the daylight hours.Minor disturbance to mice may occur whilemonitoring nocturnal species. However, thisdisturbance would be restricted to trail andbuilding areas and would not have any long termconsequences.

Indirect - No indirect effects are anticipatedfrom helicopter activity or monitoring activities.

Sub - Issue 8 - FloraDirect – The Island Malacothrix is an annual

species that would not be growing or in bloomduring the application window. It would not besusceptible to the rodenticide and would notabsorb any residues. It may be susceptible totrampling damage during the monitoring periodafter the bait has been applied and the growingseason has started.

Indirect - Soil compaction from repeatedfoot traffic over the growing areas of the IslandMalacothrix could result in increase waterrunoff, leading to increased erosion during therainy season, resulting in degraded habitatimpairing productivity of this species.

Mitigation – To mitigate against any damage tothis species, NPS botanists will identify andmark known locations of the malacothrix.Personnel working on Middle Anacapa Islandwill be advised of the presence of the plant andwill be briefed thoroughly on techniques tominimize trampling of the area surroundingmalacothrix locations.

Effects Common To Alternatives 3and 5: Bait Stations

The use of bait stations on top of East andMiddle Islands is common to both alternatives 3and 5. In these alternatives, bait stations wouldbe placed at equal distances on a grid patternaround the island. The stations would bechecked daily until the activity (bait removal)ceases or declines precipitously. Then the


CHAPTER FOUR - 56

stations would be checked monthly throughoutthe year until the following year when theywould be re-armed and checked during the aerialbroadcast operations.

Sub-issue 1 – Marine MammalsNo direct and indirect effects because bait

stations are on top of island, well away fromflushing distances to the haul-outs.

Sub-issue 2 - InvertebratesNo impact to this group is expected from

placing and checking stations.

Sub-issue 3 – FishesNo direct or indirect impacts, bait stations

are in the terrestrial environment.

Sub-Issue 4 – HerpetofaunaDirect - There would likely be disturbance

to those individuals that are along the trailnetwork used to gain access to bait stations.

Indirect - There would be no indirectimpacts to this group.

Sub-Issue 5 – SeabirdsPelagic Seabirds

Direct - There would be no impact to thepelagic seabirds, these species would beforaging offshore during the initial baitingperiod. The monthly checks of the bait stationswould likely overlap with the breeding season.If the pelagic birds are nesting on top of theisland, crews moving between stations maydisturb birds, and cause them to flush.

Indirect - The birds would likely return totheir nests once the disturbance is passed.

Roosting Seabirds

Direct - There would be minor disturbanceto nesting Western Gulls on Middle and EastAnacapa Island during the bait station checks.

The impact of the disturbance would be flushingfrom territories, however, this is believed not tohave a great impact because gulls are routinelydisturbed by visitors to East Anacapa Island withno detrimental impact.

Roosting Brown Pelicans would be flushedfrom roosting locations. The use of bait stationswould require frequent checks and would resultin frequent disturbances to pelicans.

Indirect Effects – Daily checks of baitstations would occur over the winter into theearly spring when nesting by Western Gulls hasbeen initiated. Regular station checks couldpotentially lead to nest abandonment or foropportunistic predation by other species as aresult of disturbance.

The chronic disturbance to roosting pelicanscould result in roost abandonment. Roostabandonment would be insignificant as there arealternative roosting areas around Anacapa Islandsuch as on West Island which would not bedisturbed from bait station use.

Sub – Issue 6 - LandbirdsDirect - Repeated disturbance to birds

nesting or establishing nesting territories maycause nest or territory abandonment. However,it is believed that there would be no significantdisturbance to any of the species to cause nest orterritory abandonment. During the breedingseason, the checks of the bait stations would beintermittent.

Indirect - There would be no indirect effectsexpected because of the low direct impacts.

Sub - Issue 7 - Terrestrial MammalsDirect - No impacts to the deer mouse is

expected. This species is nocturnal, all checkswould be conducted during daylight hours. Themice would be in their burrows.

Indirect - No indirect effects are anticipatedfrom repeated checking of bait stations.


CHAPTER FOUR - 57

Sub - Issue 8 - FloraDirect – The Island Malacothrix is an annual

species that would not be growing or in bloomduring the application window. It may besusceptible to trampling damage during themonitoring period after the bait has been appliedand the growing season has started.

Indirect - Soil compaction from repeatedfoot traffic over the growing areas of the IslandMalacothrix could result in increase waterrunoff, leading to increased erosion during therainy season, resulting in degraded habitatimpairing productivity of this species.

MitigationTo mitigate against any damage to this species,NPS botanists will identify and mark knownlocations of the malacothrix. Personnel workingon Middle Anacapa Island will be advised of thepresence of the plant and will be briefedthoroughly on techniques to minimize tramplingof the area surrounding malacothrix locations.

Toxicological ImpactsIntroduction

The main toxicological issue associatedwith the Anacapa Island Restoration Project isthe potential impact to other wildlife speciesfrom rodenticide exposure. For the purpose ofthis analysis, incidental wildlife speciespotentially at risk of exposure to the rodenticideare defined as non-target species. To fully andeffectively present the potential toxicologicalimpacts to non-target species, this section isorganized to give background into thebiochemistry of the rodenticides, followed by arelative comparison of toxicological impacts byalternative. Within the relative comparison oftoxicological impacts section, the potentialdirect (primary) and indirect (secondary)exposure to the rodenticides is analyzed byalternative. In the last section, the analysiswould focus on the direct and indirect

toxicological impacts presented by therespective sub-issue.

BiochemistryThe proposed action and alternatives have

outlined the use of second generation and firstgeneration anticoagulant rodenticides. Theanticoagulants act by blocking the vitamin Koxidation-reduction cycle in the livermicrosomes, preventing the production ofactivated clotting factors (Thijssen and Baars1989). Death results not from the activeingredient itself, but the uncontrolled bleedingafter tissue damage (Brown et al. 1988). For anon-target species to be at risk of hemorrhaging,it would have to consume a minimum amount ofthe anticoagulant. Before any symptoms ofanticoagulant poisoning are measured, athreshold level (concentration in the liver) mustbe reached. Symptoms include, but are notlimited to, increased time to clotting(prothrombin times (PT) ) leading tohemorrhaging. A minimum amount of activeingredient needs to be consumed, absorbed andbound in the liver, and significantly decrease theproduction of active clotting factors resulting inan increased prothrombin time, before anindividual is considered at risk of hemorrhaging.Thus, organisms are able to tolerate sub-lethallevels of anticoagulants without displaying anysymptoms of poisoning. Above that threshold,the risk of hemorrhaging is high and measurable(eg. increased clotting time). Once at risk ofhemorrhaging, activity is required to inducehemorrhaging and subsequently mortality(spontaneous hemorrhaging is possible, i.e.,although low activity, hemorrhaging stilloccurs). Without the presence of enoughanticoagulant the induction of hemorrhaging,and subsequently mortality would not occur.Thus, all animals are able to tolerate some levelof anticoagulant rodenticide exposure withoutrisk of hemorrhaging. The level of risk isdetermined by the toxicity of the chemical andthat individual’s exposure. This analysis will


CHAPTER FOUR - 58

focus on the potential primary and secondarypoisoning risks to the wildlife resources.

The relative risk of non-target speciespoisoning on Anacapa Island is determined by anumber of variables including the toxicity andexposure to the rodenticide. Exposure isdetermined by the availability of the activeingredient in both space and time. Primarypoisoning occurs when species feed directly onthe bait. Secondary poisoning occurs whenanimals feed on primarily poisoned organismsthat have rodenticide residues in their tissue.The potential of tertiary and quaternarypoisoning exists (eg. birds or mice that consumecarrion insects, containing residue of activeingredient after digesting a primarily poisonedmouse, would be tertiarily poisoned) but has notbeen thoroughly documented. For the purposeof this analysis, the risks of primary andsecondary exposure to the rodenticides will beinvestigated as per Record and Marsh (1988).Primary exposure to the rodenticides isdetermined in part by:

� Toxicological properties of therodenticide

� Bait composition and delivery into theecosystem

� Non-target species behavior andforaging strategy

� Local environmental factors;

Secondary exposure to the rodenticides isdriven by any one species primary exposure tothe rodenticides. In addition to the abovefactors, the behavior and location of death of thetarget species will influence secondarypoisoning.

Relative Comparison ofToxicological Impacts byAlternativeThis section will compare the potentialtoxicological impacts by alternative. Under thefeatures common to alternatives 2 – 6, each

section will evaluate the variables (toxicology,bait composition, behavior of species and localfactors) that contribute to risks of non-targetspecies exposure to the rodenticide. This sectionwill follow with a breakdown of toxicologicalimpacts by sub-issue. Where possible, an acuterisk of exposure to the rodenticides was evaluatedfor each sub-issue and rodenticide.

Alternative 1 – No ActionUnder this alternative, there would be noapplication of rodenticides, therefore there wouldbe no toxicological impacts.

Features Common to Alternatives 2,3, 4, 5 and 6

Primary ExposureToxicology

The rodenticides are vertebrate toxicants.All the rodenticides presented in the alternativesare toxic to all the vertebrates, provided they areexposed to the rodenticide in sufficientquantities. The toxicity to both the target andnon-target species will determine the relativeprimary and secondary exposure risks. The risksof exposure to the anticoagulants is determinedby how well the non-target species is able tometabolize and excrete the compound, which is

________________________________________

Table 8. Primary exposure index for eachalternative

Alternative1 2 3 4 5 6

Ranking(Low toHighest)

1 4 2 6 5 3

________________________________________


CHAPTER FOUR - 59

a function of its acute toxicity. Further analysiswill be presented by sub-issue (see below).

Bait Composition and Delivery into theEcosystem

The bait composition and method ofdelivery into the ecosystem would influencehow and if species are primarily exposed. Thebait formulation (inert products, size of pellet)and method of dispersal into the Anacapaecosystem would determine the relative primaryexposure risks. For example, granivorousspecies would be more interested in rodent baitcomposed of a compressed grain pellet vs a highprotein “meat” bait. The insectivorous, orcarnivorous, species may “avoid” a bait that iscomposed of compressed grain. Similarly, sizeof the bait itself plays an important role indetermining if a species may be exposed to thebait itself. The smaller species may not bephysically able to consume the bait due to itssize, in contrast, the larger species may not beinterested in small pelleted bait if available.Thus, some species are “ protected” fromfeeding on the bait because of its size. Under allalternatives, the bait would consist of acompressed grain pellet and could be attractiveto most granivorous/omnivorous species capableof ingesting that size pellet. Alternatives 3 and 5would see the use of a block that is larger thanthe pellets and would limit further species fromconsuming the bait.

How bait is delivered into the AnacapaIsland ecosystem would determine the scale ofpotential rodenticide exposure. The alternativesoutline the use of aerial/hand broadcast and baitstations for delivery of the rodenticide ontoAnacapa Island. The aerial broadcast of therodenticides has been demonstrated to representa risk of non-target exposures to the rodenticides(Edward et al. 1988).

A risk index (Edward et al. 1988) to providea measure of primary exposure risk whenevaluating rodenticides was utilized to qualify

the relative primary exposure risks among thealternatives. The risk index takes into accountbait concealment ( C - scored 1 to 3, high tolow), quantity of bait placed (Q), and numbersof animals present (N). Using these factors, theequation:

3 (C x Q x N)

can be utilized to evaluate the relative primaryexposure risks. For the purpose of this analysis,the primary poisoning risk index was calculatedfor each alternative using: 3 for low concealment(aerial) 1 for high concealment (bait stations),bait quantity per hectare applied, and assumesthat only one non-target animal is present. Forthe alternatives with both bait stations and aerialapplication (alternatives 3 and 5), and alternative6 (two different rodenticides), the risk index wascalculated for each application technique and/orrodenticide, and averaged. The scores wereranked from lowest primary exposure risk tohighest for comparative purposes (Table 8).

The risk of primary exposure is highestunder alternative 4 and lowest under alternative3. The highest risks of primary exposure occurswhen the rodenticide is broadcast, and lowestwhen presented in bait stations. Presenting baitin tamper proof bait stations limits access of thebait to rats and species smaller than rats (such asdeer mice and invertebrates). The use of baitstations would lower the scale of rodenticideexposure, but it would not reduce the risk ofexposure to zero. Although the relativeexposure risks between the alternatives vary, itwould be impossible to preclude the possibilityof exposure. The Risk Index is useful as a toolto evaluate the primary exposure risks, alone itdoes not provide an adequate measure of therelative risks.


CHAPTER FOUR - 60

Behavior of Non-Target SpeciesThe behavior of the non-target species and

their associated foraging strategy is an importantdeterminant in risk evaluation. The hazard ofthe rodenticide is a function of toxicity andexposure (Record and Marsh 1988). Althoughthe toxicity of a rodenticide is high in somecases, the non-target species needs to be exposedto the rodenticide to be considered at risk.Exposure may not occur if the species is notpresent during the baiting operation, or does notfeed on the bait or a primarily exposedorganism, thus avoiding both primary and/orsecondary exposure.

Local Environmental FactorsExposure to the rodenticide, primary or

secondary, is determined by the availability ofthe rodenticide in space and time. Theconditions of the local environment willinfluence the availability of the rodenticide byenhancing the degradation of any residual bait(or not). The application rate was determined byconsumption rates of rats and mice over a 4 dayperiod. The majority of the bait will beconsumed by rats and mice, leaving few pelletsin the environment. The combination of rainfall,fog and invertebrates will degrade the remainingbait pellets. The application will take place priorto the rainy season such that any remaining baitwill absorb moisture and break up. Thepresence of moisture would encourage mold andmicrobial degradation of the rodenticide to itsbase components of water and carbon dioxide.Bait will not likely be present on Anacapa by theend of the rainy season.

Similarly, the timing of the operation willinfluence the scale of potential primary andsecondary exposure risks. For example,migratory species may not be present during theaerial application window and therefore wouldnot be exposed. Conversely, the use of baitstations over time would potentially put thosespecies at higher risk.

Consequence of Primary ExposureMany variables must be taken into

consideration when evaluating the primaryexposure to the rodenticides. The consequenceof primary exposure to the rodenticides may bean anticoagulated state leading to hemorrhagingand mortality. To characterize the consequenceof primary exposure to the rodenticides, thetoxicology data and exposure data (based onallometric equations (EPA 1993) were used tomodel the number of LD50s individuals would beexposed to if they fed exclusively on therodenticide bait for one day.

Risk quotients (RQs) were calculated bydividing the exposure estimates with ecotoxicityvalues:

RQ= Exposure/Toxicity

For the purpose of this discussion, anestimate of the primary poisoning risk to thebirds and mice were estimated by calculating thenumber of LD50s/day a bird would likely beexposed to if it fed exclusively on the bait, usingthe following formula:

LD50s/day = mg rodenticideconsumed/day ÷ [LD50 x weight (kg)]

Where mg rodenticide consumed/day = amountof bait eaten x % active ingredient in the bait.Allometric equations were used to estimateamount of bait consumed daily (EPA 1993). Ifno LD50 data existed for that species, the LD50

from the species in closest taxonomicrelationship was used consistently for eachrodenticide (eg. Laboratory rat LD50 data usedfor brodifacoum, bromadiolone andDiphacinone). However, caution must be usedwhen interpreting this data because phylogeneticrelationships cannot be used to predictsensitivity to the rodenticides (Hill 1994;Mineau, 1991). To more precisely present therelative risks of poisoning to non-target birdspecies, the LD50 data was statistically“corrected” following Mineau et al. (2000).


CHAPTER FOUR - 61

For regulatory purposes, the EPA evaluatesthe Risk Quotients and compares them to theOffice of Pesticide Programs Level of Concerns(LOCs). LOCs are evaluated as: Acute HighRisk (LOC >0.5), Acute Restricted Use (LOC>0.2), and Acute Endangered Species (LOC>0.1). It is on this evaluation that the EPArestricts certain pesticides from certain usepatterns or availability to public or professionalpest control uses. For the purposes of thisdiscussion, any rodenticide with a RQ >0.5 ispresumed to put that group of species at risk oflethal poisoning.

Secondary ExposureToxicology

Brodifacoum and bromadiolone are secondgeneration anticoagulants while diphacinone is afirst generation anticoagulant. In general, thedifference between the two categories is thetoxicity and the sensitivity to metabolism whichis reflective in the toxicity. Upon ingestion andabsorption, the anticoagulants bind to a“warfarin binding” protein in the livermicrosomes where they act to prevent the

production of active clotting factors. The firstand second generation anticoagulants both bindat this site and the difference between thechemicals is their binding affinity at this site.Brodifacoum has a greater affinity thanbromadiolone and both have a much higheraffinity than diphacinone. Diagrammatically:

Brodifacoum>Bromadiolone>>>>Diphacinone.

This binding affinity may be the reason thatthe second generation anticoagulants aresignificantly more toxic. In general, the strongerthe binding affinity, the higher the toxicity. Thebinding affinity is also related to the ability ofthe organism to metabolize and excrete thecompound. The stronger the binding affinity,the greater the resistance to metabolism oncebound. Thus, the ability to metabolize

Diphacinone>>>>Bromadiolone>Brodifacoum.

The implications of the sensitivity ofmetabolism is that relative risks of secondarypoisoning vary between the rodenticides. Forexample, mortality was found in barn owls fedbrodifacoum (5/6) and bromadiolone (1/6) dosedrats but no mortality was detected in barn owls(0/2) fed diphacinone dosed rats (Mendenhall

Table 9. Properties of the rodenticides affecting their potential for secondary poisoning.

Active Ingredient (Rodenticide)Brodifacoum a Bromadiolone Diphacinone

Alternative 2, 3 and 6 Alternative 4, 5 Alternative 6

Sensitivity toMetabolism Low Low High

Tissue Retention High High Low

Biological Half-Life Long Long Short

Estimated time 150-200 days (RED1998)

318 days (RED1998).

15-20 days (WHO1995)


CHAPTER FOUR - 62

and Pank 1980). This is suggestive also of thepotential secondary poisoning impact of singleversus multiple exposures to the rodenticides.Brodifacoum would have a higher potential forsecondary exposure impact after a singleexposure, while diphacinone may requiremultiple exposures to illicit the toxic effect.With brodifacoum and bromadiolone, becausedeath is delayed between 3-10 days (for rodentsand birds), they would continue to feed on thebait long after a lethal dose has been ingested,allowing for accumulation of the rodenticide inthe carcass and liver. With diphacinone, thehigh rate of excretion and metabolism does notallow for significant levels of residues toaccumulate in the carcass, although residueswould be present and would present a secondarypoisoning hazard. Diphacinone bait requires ratsto feed on the bait over a period of up to 7daysto illicit the toxic response. During that period,the rats are rapidly metabolizing the compound.Because ingestion is believed to be faster thanmetabolism, rats will eventually reach thethreshold and a toxic response is measurable,

potentially negating the secondary poisoning“protection”. In comparison, brodifacoum andbromadiolone are “single-feeding”anticoagulants and are capable of illiciting atoxic response to the target species after a singlefeed. Table 9 summarizes the factors affectingthe secondary toxicity of the rodenticides in thealternatives.

The low sensitivity to metabolism, highretention of residues in tissue and longbiological half life of the second generationanticoagulants present a secondary exposurehazard to species preying on primarily exposedorganisms. Godfrey (1985) demonstrated thatmost of brodifacoum administered to rats thatsurvived the dosing was retained up to 10 daysafter administration. Sheep dosed withbrodifacoum at 2 mg/kg showed liverconcentrations of 2 mg/kg four months later(Rammell et al. 1984). However, the biologicalhalf life must be qualified. For a sub-lethallyexposed organism, the decline of theanticoagulants have been demonstrated to be bi-

______________________________________________________________________________

Table 10. Potential for accumulation of the rodenticides for the different sub-issues.


Brodifacoum Bromadiolone DiphacinoneSub-Issue Alternative 2, 3 and 6 Alternative 4, 5 Alternative 6

Marine Mammals High High Low

Invertebrates Low Low Low

Fishesa High High Low

Herpetofaunaa High High Low

Birds High High Low

Mammals High High Low

a No literature data available, however, estimated to follow similar pattern as for mammals and birds.


CHAPTER FOUR - 63

phasic – a rapid phase (in which the majority oftoxicant is excreted) followed by a very slowphase (lower toxicant loading in the tissue)(RED 1998). Diphacinone, with its highsensitivity to metabolism, low tissue retentionand short biological half-life, would notaccumulate in predators as brodifacoum orbromadiolone. In other words, diphacinoneoffers greater secondary exposure protectionthan do either bromadiolone and brodifacoum.Thus, the second generation anticoagulantspresent a short term and long term non-targetsecondary poisoning potential and have thepotential to present a poisoning hazard to non-target species especially through cumulativeexposures.

The potential for accumulation and retentionof the rodenticides for each of the species in thesub-issues is outlined in Table 10. Theinvertebrates are expected to accumulateminimal if any residue (Pain et al. 2000, Howald1997). The residues available in theinvertebrates are believed to be restricted to thepresence of the chemical in the gut of theorganism. Thus, digestion time of the bait is thecritical period as a secondary exposure hazard.

Composition of Bait and how it is AppliedThe above analysis demonstrates that the

anticoagulant rodenticides represent a potentialsecondary poisoning risk to non-target species.However, the levels of residues found withincarcasses can be mitigated through alteration ofconcentration of active ingredient and itsapplication technique. From a secondarypoisoning perspective, by decreasing theconcentration of active ingredient applied, theresidue body burden found in target speciescarcasses is lessened. For example, Kaukeinen(1982), fed voles 10 ppm and 50 ppmbrodifacoum bait. The brodifacoumconcentrations were 4-10 fold more in thosevoles that fed on the 50 ppm brodifacoum bait.

Thus, the concentration of the active ingredienthas a secondary poisoning consequence.

The delivery of the bait onto Anacapa Islandwould occur by one of two methods: aerialbroadcast and/or in combination with baitstations. Eradication of rats using the baitstation approach would be a saturation baitingstrategy where an “unlimited” supply of bait isoffered until activity ceases or slows, then thefrequency of checking and re-arming of baitstations is reduced. This allows for thepossibility of “overkill” where rats are able toconsume as much bait as they desire. Recently,Howald et al. (2000) evaluated the brodifacoumresidue levels within Norway rat carcasses afteran eradication effort from a large seabird colonyusing bait stations. The residue concentrationlevels within the carcass were partitionedequally in the liver (site of activity) and gastro-intestinal tract (primarily from unassimilatedbait). Unassimilated bait found in the gut of ratsfound dead above ground, represented 30-50%of the total brodifacoum residue load, andreflected the saturation baiting strategyemployed. The aerial application of therodenticide may potentially limit theconsumption of bait by rats with less chance ofoverkill and thus limit the residue loading in anyone carcass (Record and Marsh 1988). Thelevels of the rodenticides that may be found in

___________________________________________

Table 11. The relative secondary poisoning potentialover time.

Alternative

1 2 3 4 5 6

Temporal NA Short Long Short Long Short

___________________________________________


CHAPTER FOUR - 64

rats and mice cannot be readily predicted foreach of the alternatives.

On Anacapa, rats may consume all the baitbefore mice have access to it, versus in a baitstation where bait would be available in stationsfor mice long after rats have been eradicated.The presence of bait in stations in the long termwould present a long term secondary poisoningpotential, possibly outweighing the short termsecondary poisoning potential (Table 11). Inother words, the window of secondary poisoningfrom toxic rats and mice would be shorter with asingle aerial broadcast, and longer with baitstations. For a successful eradication using baitstations, stations must be armed for well over ayear, perhaps two (Kaiser et al. 1997, D. Veitch,pers. comm., R. Taylor, pers.comm.). Once ratshave been eradicated, and mice begin to usestations and die, other mice would fill thoseterritories, enter the stations, and consume bait.On Anacapa, the secondary poisoning potentialfrom bait station delivery is determined by thelength of time stations are left armed.

Behavior of Target Species on Intoxicationand at Death

The risk of secondary poisoning topredators/scavengers of rats and mice is limitedby the availability of these prey in space andtime. For the aerial predators on Anacapa, theirsearch image is for live prey and thus risk ofpoisoning is during the latent period (after ratsand mice have consumed the bait, but have notyet died) (estimated at 2 weeks). Anticoagulatedrats demonstrate altered behavior whichpotentially makes them more susceptible topredation and scavenging. For example,Norway rats exposed to a lethal dose ofbrodifacoum spent significantly more time inopen areas, sitting motionless or staggeringabout (Cox and Smith 1992, Gemmeke 1990).Most Norway rats radio-tagged in the fieldbefore baiting died underground in their burrows(87 – 100%) (Howald 1997, Taylor 1993).However, laboratory studies have demonstrated

up to 50% die in the open (Cox and Smith 1992;Gemmeke 1990). Thus, anticoagulant poisonedrats and mice would be available to both diurnaland nocturnal predators and scavengers. OnAnacapa, islet wide treatment would yieldnumerous dying rats and mice displaying erraticbehavior and likely would be a significant preybase because of the ease of catching them.Optimal foraging theory indicates that anindividual would use an area for foraging thatwould provide the greatest yield. Similarly, anumber of rats and mice would die aboveground and available for diurnal scavengers.

Local Environmental FactorsThe above analysis has demonstrated a risk

of secondary exposure to the rodenticides,however, it does not consider the localconditions at the time of the application window.The late fall period corresponds to the late dryseason, which is a time when conditions formost species can be difficult. Both the rat andmouse population would be at the lowest pointin their annual cycle which would limit thenumbers of poisoned rats and mice available toavian hunters and scavengers on the island. Theonset of the rainy season soon after the bait hasbeen applied will degrade the bait thus limitingthe potential primary and secondary exposure.

Toxicological Impacts by Sub-IssueThe analysis is broken down into the sub-

issues, and within each sub-issue, broken downinto primary and secondary exposure. Theconsequence of rodenticide exposure for eachsub-issue, where possible, was calculated and isrepresentative of a “worst-case” scenario.Where the Level of Concerns (LOC) exceed 0.5,suggested mitigation measures are presented.

Sub-Issue 1: Marine MammalsPrimary Exposure (Direct)

The risk of primary exposure to thepinnipeds is the same across all alternatives


CHAPTER FOUR - 65

because of the aerial broadcast of therodenticides onto the cliffsides. Alternative 6 isa higher risk for exposure because of themultiple treatments with both diphacinone andbrodifacoum.

Toxicology - No data exists on the toxicityof the rodenticides to marine mammals. Ifconsumed in sufficient quantities, therodenticides are likely toxic to the seals and sea,impairing hemostasis as in the other vertebrates.

Bait Composition and Delivery - The aerialapplication of the rodenticides onto the cliffsidesand shoreline of the islands present a risk thatbait may drift into the ocean or land on thebeach areas where marine mammals feed andhaul out. Therefore, this group is at risk ofprimary exposure if they were to be attracted tothe bait.

Behavior and Foraging Strategy - Thepinnipeds feed exclusively in the marineenvironment, and only haul out to rest andbreed.

The diet of the California Sea Lions andHarbor Seals is primarily composed of fish and

other animal species, however, it is unknown ifthey would be interested in bait pellets fallingthrough the water column if they were to driftinto the marine environment. The bait is a grainbased pellet, that would unlikely be attractive tothe seals and sea lions. The primary exposureof the seals and sea lions to bait while hauled outon shore is believed to be very low. The sealsand sea lions would be utilizing the haul-outsaround Anacapa Island during the proposedperiod of baiting.

Rodenticide Exposure Risk - The sea lionsand seals are at low risk of primary exposurebecause of their foraging strategy. Calculatingtheir risk quotient assuming a “worst casescenario” where they would feed exclusively onthe pellets revealed that their exposure fallsbelow the EPA LOC of 0.5 for all rodenticides(Figure 11).

Secondary Exposure (Indirect)The diet of the California Sea Lions and

Harbor Seals is primarily composed of fish andother animal species. Sea lions and seals areabundant around Anacapa Island during theproposed application window. If fish,predominantly sheephead, were to be primarilyexposed to the rodenticide, the seals and/or sealions may feed on the fish and be secondarilyexposed to the rodenticide. This scenario is

______________________________________________

Table 12. The 48 hour LC50/EC50 (ppm) for freshwaterinvertebrates (from RED 1998).

Active IngredientSpecies Brodifacoum Bromadiolone Diphacinone

WaterFlea

(Daphniamagna)

0.98 0.24-2 1.8

___________________________________________________

_______________________________________________

Figure 11. Risk Quotients for Harbor Seals

0.13 0.12

0.03

0.13 0.12

0.03

0.0000

0.1000

0.2000

0.3000

0.4000

0.5000

0.6000

0.7000

0.8000

0.9000

1.0000

25 ppm Brodifacoum 50 ppm Bromadialone 50 ppm DiphacinoneRodenticide

RQ

Theoretical Minimum

Theoretical MaximumEPA LOC (0.5)


CHAPTER FOUR - 66

believed to be an extremely low probabilitybecause of the low probability of fish primaryexposure – see above.

Sub-Issue 2 – Invertebrates

Primary Exposure (Direct)Toxicology - Limited data exists on the

acute toxicity of the rodenticides to theinvertebrates. The EPA released data outliningthe acute toxicity of the rodenticides to the waterflea, a freshwater invertebrate (Table 12). Noother invertebrate toxicology data is available.

The anticoagulant rodenticides are notknown to affect the terrestrial and intertidalinvertebrates because of their different bloodclotting systems (Shirer 1992). Extensive fieldand lab trials have shown that beetles (Morganet al. 1996; Eason and Spurr 1995; Stejskal et al.1994; Tershy et al. 1992), cockroaches(Godfrey 1985), wetas (Morgan et al. 1996),land crabs (Pain et al. 2000; D. Veitch pers.comm.), snails, slugs, orthopterans, millipedes(Howald 1997), and ants (Godfrey 1985; Tershyunpubl. data) are attracted to rodent baits andcan survive on a diet of 20-50 ppm brodifacoum.

Bait Composition, Delivery and Behavior -This sub-issue combines both the marine andterrestrial invertebrates. The terrestrialinvertebrates would play a significant role in theremoval of residual bait that is not consumed byrats and mice. A wide range of invertebratespecies would consume bait and may transportthe rodenticide into the ecosystem (seeSecondary Poisoning). Limited studies onAnacapa Island in 1999 showed that sowbugsare attracted to placebo bait (ICEG 2000). Theinvertebrates on Anacapa Island would play asignificant role in removal of residual bait that isnot consumed by rats and mice.

There is a risk that some bait may enter intothe intertidal zone and ocean around theAnacapa Island. If bait were to enter, the marinefauna would likely be a significant factor in

consuming any bait pellets. There would likelybe no direct impacts to individual species astheir blood clotting mechanisms are comparableto the terrestrial species (Shirer 1992).

The consequence of rodenticide ingestionappears to be insignificant to the invertebrates.However, the consumption of the bait byinvertebrates may have significant consequencesfor species that prey on those species, potentiallymoving the rodenticide into the ecosystem.

No RQs were calculated because of lack ofacute toxicity data and the apparent lowsusceptibility to the anticoagulant rodenticides.

Secondary Exposure (Indirect)The invertebrates would play a significant

role in the removal of carcasses containingresidues of the rodenticides, thus would besecondarily exposed. The invertebrates wouldingest the rodenticide, however, they would notcarry significant levels of residues outside theresident time in the gut of the organism (Pain etal. 2000; Morgan et al. 1996). They wouldpresent a risk of movement of the rodenticideinto the ecosystem.

Sub-Issue 3 – FishesPrimary Exposure (Direct)

Toxicology - No data is available on thetoxicity of the rodenticides to marine fishes,however, data is available for freshwater species(Table 13).

Bait Composition, Delivery and Behavior -The drift of bait pellets into the marineenvironment from aerial broadcast is possible.The fish in the nearshore waters off of AnacapaIsland are at risk of primary exposure throughconsumption of bait pellets that may fall throughthe water column. A small study was initiated in1999 to identify those fish species that mayconsume bait (Table 14; ICEG 2000). Placebobaits were hand broadcast in small areas, thespecies present tallied along with their reaction


CHAPTER FOUR - 67

to the bait pellets. The majority of the pelletsthat were falling through the water columnillicited no response from marine fishes (62%).However, baits falling through the water columnillicited an “inspection” response 20% of thetime (inspection defined as approaching orfollowing the pellet and/or “kissing” the pellet).Only sheephead was noted to actually take inand break up the pellet, but did not apparentlyconsume the bait. Based on these results,sheephead is the only species to be considered atprimary exposure risk if bait enters the marineenvironment. However, it is recognized thatother species, or larger individuals of the speciescould be interested in bait pellets. Fish may alsobe at risk of exposure through the absorption ofrodenticide residue across their gills if a highenough concentration is found within the watercolumn. All the rodenticides in the alternativesare slightly to highly lipophilic and wouldtherefore not be found in significantconcentration in the water column. Any baitfalling into the ocean would rapidly absorbmoisture and begin to breakdown. Studies withplacebo baits has shown that a compressed pelletlasts up to a “few hours” in calm conditions onthe ocean floor (B. Keitt, pers.comm.). Theincessant wave action and persistent swells onAnacapa Island would expedite the degradationprocess. On breakup of the bait pellets, the

rodenticides, are not water soluble andwould not readily stay in the water column,rather, begin to bind to available organicmatter – such as marine animals and in thebenthic layer. Therefore, the probability ofa high enough concentration of rodenticideto enter into the sea and be of high enoughconcentration to be absorbed across thegills or skin of fish is low.

Secondary Exposure (Indirect)Predatory fish may consume any

primary exposed fish and/or other prey andare secondarily exposed to the rodenticide.However, this event is not likely to be

extensive and would not likely adversely affectany local populations.

Sub-Issue 4 – HerpetofaunaPrimary Exposure (Direct)

Toxicology - No LD50 data exists for theherpetofauna, however, studies havedemonstrated equivocal results. In NewZealand, skinks found dead after an applicationof brodifacoum, tested positive for brodifacoumand showed symptoms of anticoagulantpoisoning (see Eason 1995). This is in contrastto Tershy (pers. comm.) in which lizards wereforce fed 50 ppm brodifacoum bait. After twoweeks, the lizards showed no symptoms ofpoisoning. No lab data is available to evaluatepotential primary exposure.

Bait Composition, Delivery and Behavior -The three species of herps on Anacapa Island areprimarily insectivorous and are at a low risk ofprimary exposure to the rodenticide. However,during an eradication campaign in New Zealand,Telfair’s Skinks (Leiolopisma telfairii)reportedly consumed rain softened bait andsuccumbed to brodifacoum (Merton 1987 inEason and Spurr 1995). The most significantpathway for rodenticide exposure is likelysecondarily via their invertebrate prey base.

__________________________________________________________________

Table 13. The 96 hour LC50 (ppm) for freshwater fishes (fromRED 1998).

Active Ingredient

Species Brodifacoum Bromadiolone Diphacinone

RainbowTrout

0.015 0.24 2.6

BluegillSunfish

0.025 3.0 7.5

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CHAPTER FOUR - 68

If the bait would be attractive to any of thelizards or salamander, the aerial broadcast of therodenticide would increase the probability thatgreater numbers would be exposed. The use ofbait stations on top of the island would spatiallyexclude most individuals from exposure,limiting exposure only to those individuals that

have a bait station within their territory. If anindividual was poisoned, that territory wouldbecome vacant and could be filled with anotherindividual. That individual would then be athigh risk of primary exposure. With an aerialbroadcast laid out in the alternatives, the scale ofimpact would be a short window in time since

Table 14. Attraction of marine fishes to placebo baits, Anacapa Island, Spring 2000

Event

Common Name a Species Name No action

InspectedBait

TouchedBait

ChewedBait

ConsumedBait

Grand Total b

Blacksmith(391)

Chromispunctipinnis

22% 0% 0% 0% 0% 22%(11)

Garibaldi(19)

Hypsypopsrubicundus

6% 6% 6% 0% 0% 18%(9)

Kelp bass(11)

Paralabraxclathratus

6% 2% 2% 0% 0% 10%(5)

Opaleye(100)

Girellanigricans

16% 4% 4% 0% 0% 24%(12)

Senorita(7)

Oxyjuliscalifornica

2% 2% 2% 0% 0% 6%(3)

Sheephead(7)

Pimelometoponpulchrum

6% 0% 2% 2% 0% 10%(5)

Unidentified(14)

Unidentified 2% 2% 2% 0% 0% 6%(3)

Zebra perch(1)

Hermosillaazurea

0% 0% 2% 0% 0% 2%(1)

None(1)

none 2% 0% 0% 0% 0% 2%(1)

Grand Total 62%(31)

16%(8)

20%(10)

2%(1)

0%(0)

100%(50)

a Total number of individuals of a species during study in brackets.b Number of events in brackets.


CHAPTER FOUR - 69

the bait would be removed from theenvironment. Bait stations would have thepotential for long term exposure to individuals.

No RQs were calculated due to lack of acutetoxicity data.

Secondary Exposure (Indirect)The lizards and salamander are at risk of

secondary exposure through consumption ofprimarily exposed invertebrates. It is unknownif the diet of the herpetofauna is similar orcontains species that would degrade residual baitin the Anacapa environment.

Sub-Issue 5 and 6 – Seabirds andLandbirdsPrimary Exposure (Direct)

Toxicology - Toxicity data exists for bothgroups of birds (seabirds and landbirds) (Table15). Brodifacoum is the most toxic rodenticideto birds.

Bait Composition, Delivery and Behavior -(Pelagic Seabirds) The pelagic seabirds areconsidered to be at low risk of primarypoisoning because of their foraging strategywhich is almost exclusively offshore. They arealmost exclusively carnivorous, preferring liveprey. If during the aerial operations, bait was tofall into the water, and a pelagic seabird was inthe vicinity, it may mistake a pellet for aninjured fish and perhaps pursue and consume.

Most of the pelagic seabirds winter offshorefrom Anacapa Island and are at a very low riskof exposure.

(Roosting Seabirds) - The roosting seabirds,those that utilize Anacapa Island for roostingand tend to primarily feed offshore, are atgreater risk of exposure to the rodenticide thanpelagic seabirds. Recent studies documentedWestern Gulls exploring piles of placebo baitdeliberately placed near roost sites (ICEG 2000).Similarly, placebo baits that were deliberately

hand broadcast into the marine environmentcaught the attention of Western Gulls whichsubsequently investigated the bait. Theattraction of gulls to the bait falling into thewater drew more gulls into the area. However,the bait pellets fell through the water columnquickly and no gulls were observed tosuccessfully “fish” out any pellets.

The timing of the operation is late fall and earlywinter when gull numbers are at their lowest.

Brown Pelicans

There would be no direct effect of therodenticide bait on the pelicans since they arefish eaters. There is no likelihood that theywould ingest any bait directly, or secondarilyfrom contaminated prey. The bait would be in apellet form and is not expected to adhere to birdfeet or feathers, therefore, it is unlikely thatpelicans will inadvertently ingest the pelletsduring preening activities. Pelicans are notscavengers and will not eat dead and poisonedrodents. (It is expected that most (87-100%) ofrodents will die underground after consumingthe bait.) Pelican prey species are schooling fishsuch as anchovies and sardines, species whichwould not come into contact with the bait.

(Landbirds) - As a conservative estimate ofprimary exposure risks, the granivorous andomnivorous species are presumed to be at aprimary exposure risk during the operations.Over 47% of the landbirds are either granivorousor omnivorous and may be subject to primaryexposure risks on Anacapa Island (Table 16).

However, this is based upon year roundoccurrence of these species on the islands.During the proposed application period, many ofthe landbird species would have moved off theislands to their wintering grounds. On AnacapaIsland, this reduces the number of species at riskfrom 59 granivorous/omnivorous species to 26.Further, recent surveys in November/December1999 on Anacapa Island detected only 14species, including carnivorous and insectivorous


CHAPTER FOUR - 70

birds (ICEG2000). Themost abundantspecies werethe HouseFinch,Bewick’s Wrenand SaysPhoebe.

The interestin the bait bynon-targetspecies wasinvestigated inthe Fall of 1999as part of thepre-eradicationresearch.Placebo baitpellets wereplaced inexposedlocationsaround AnacapaIsland andobserved from adistance. After62 hours ofobservationtime, only onepile wasinvestigated bya Western Gull,whichapparently didnot ingest any of the pellets (ICEG 2000).However, during spring trials, placebo baitswere investigated by Western Gulls and at leastone was noted to consume pellets. No landbirdspecies were noted around the pellets during theobservation period. This data suggests that therelative risk of primary exposure to the landbirdswould be lower than suggested by the abovetable.

The RQsfor birds arepresented inFigures 12, 13,and 14. Thebird RQsexceed the EPALOC of 0.5 forbrodifacoum,andbromadiolone,falling belowfordiphacinone.This suggeststhat under theproposedalternative, if abird was to beprimarilyexposed to therodenticide,there is a risk ofhemorrhagingand mortality.

The lack ofinterest in theplacebo baits onAnacapa Islanddoes notpreclude thepossibility ofprimarypoisoning tolandbirds. Field

studies have shown that landbirds have beenexposed to rodenticides that have beendispensed in both bait stations and by broadcast.Common Ravens, wekas and keas have beenobserved reaching into, or breaking into baitstations to gain access to the brodifacoum bait(Howald et al. 2000, Eason and Spurr 1995,Taylor and Thomas 1993). The primaryexposure in combination with secondaryexposure to brodifacoum had a significant

Table 15. Acute Oral and Dietary Toxicity of Rodenticides to Birds(LD50 mg/kg) (A dash indicates that no data is available) (RED1998).


Brodifacoum a Bromadiolone DiphacinoneAlternative 2, 3

and 6Alternative 4

and 5Alternative 6Species

LD50 LC50 LD50 LC50 LD50 LC50

Mallard 0.26 2.0 - 158 3158 906

NorthernBobwhite - 0.8 138 37 >400 -

<2000 >5000

CanadaGoose <0.75 - - - - -

Black-backed Gull <0.75 - - - - -

LaughingGull 0.7 - - - - -

CaliforniaQuail 3.3 - - - - -

Ring-neckedPheasant

10 - - - - -

HarrierHawk 10 - - - - -

HouseSparrow >6 - - - - -

a The LD50 for an unknown bird species has been estimated to be above0.56 mg/kg (see Howald et al. 2000)

__________________________________________________________


CHAPTER FOUR - 71

impact on the local populations. These speciesare large, aggressive and share an omnivorousdiet which contributed to their decline. Primaryexposure and some mortality of birds of varyingsizes, foraging strategies and classificationsincluding: Kiwi, South Island Robins, weka,North Island Saddlebacks, blackbirds,chaffinches,House Sparrows,HSparrows, Australian Magpie,Paradise Shelducks, and Pukekohave been reported (Empson andMiskelly 1999; Dowding et al.1999; Eason and Spurr 1995;Morgan et al. 1996). All weresuspected or confirmed exposed tobrodifacoum, applied both aeriallyand in bait stations, and used for rateradications from islands. Althoughthe above studies have documentedexposures and some mortality ofthese species from rodenticideexposure, the significance of theextent of poisoning was variedranging from significant mortality(Howald et al. 2000; Eason andSpurr 1995; Empson and Miskelly

1999), to minor and insignificant(Robertson et al. 1993; Robertson et al.1999; Dowding et al. 1999; andEmpson and Miskelly 1999). Althoughthere were incidences of poisoning inmost island eradications, some impactedspecies recovered to population densitieswhich were higher than densities beforerodenticide application. (Empson andMiskelly 1999; Robertson et al. 1999;B. Simmons, pers. comm.)

In summary, landbirds will beexposed to the rodenticides on AnacapaIsland. The consequence of suchexposure would depend on therodenticide. Brodifacoum andbromadiolone would result in mortalityto some individuals, through single andcumulative exposures. The risk of

primary poisoning would be significantly lesswith the use of diphacinone.

Secondary Exposure (Indirect)(Pelagic Seabirds) - The risk of secondary

exposure to the pelagic seabirds is throughconsumption of primarily exposed fish. The

Figure 12. Risk quotients (RQ) for 20-50 g birds

7.81

0.61

0.05

3.13

0.02

0.24

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

25Brodifacoum

50Bromadialone

50Diphacinone

Concentration (ppm) of Rodenticide

RQ

Theoretical Maximum

Theoretical Minimum

EPA LOC (0.5)

Figure 13. Risk Quotients (RQ) for 100-200g birds

4.02

0.02

2.01

0.01

0.31 0.16

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

25Brodifacoum

50Bromadialone

50Diphacinone


RQ

Theoretical MaximumTheoretical Minimum

EPA LOC (0.5)


CHAPTER FOUR - 72

foraging grounds and the size of the prey wouldlimit the potential for exposure. Most of thesmaller seabirds take small prey such as sardineswhich would not be able to consume the baitpellets. The risk of secondary exposure to thesespecies is very low.

(Roosting Seabirds) - Western Gull is theonly species believed to be at risk of secondaryexposure in the terrestrial environment viaconsumption of primarily exposed mice. Nogulls were observed to consume any snap-trapped mice placed out in open areas, however,one was noted to pick up and drop a mousecarcass (ICEG 2000).

In the marine environment, if fish were to beextensively primarily exposed and were to floaton the surface of the ocean, gulls would likelybe an important scavenger that would consumethe fish.

(Landbirds)- The birds of prey andscavengers are at risk of secondary exposurethrough predation/scavenging of live/dead miceand rats containing rodenticide residues (Table17). Smaller landbirds such as the insectivores

are at risk of secondaryexposure throughconsumption ofinvertebrates that wouldhave rodenticide residuesin their digestive tract,however, the extent of thisis believed to be relativelyinsignificant.

During the pre-eradication research,11mice and 14 ratcarcasses were observedfor 165 hours to identifyscavengers. The CommonRaven and AmericanKestrel were the onlylandbird species observedto scavenge rats and mice

(ICEG 2000). On Anacapa, only one pair ofCommon Ravens were observed, and AmericanKestrels were in low abundance, not evenshowing up in the bird surveys conducted inNovember/December 1999 (ICEG 2000). Thebirds of prey also were in low abundance, amaximum of 3 Burrowing Owls, 2 Short-earedOwls, and a pair of Barn Owls were observed onEast Anacapa Island; Red-tailed Hawks andNorthern Harriers were also in low abundanceduring fall surveys. This indicates that althoughthere is a risk of secondary exposure to thesespecies, the relative number of species presenton the island during the proposed applicationperiod is low.

It seems reasonable to expect a significantimpact on any species that preys primarily onrats and/or mice on Anacapa Island ifbrodifacoum is used. The relative risk would beless, although not absent with bromadiolone.The eradication of rats from East Island with afollow up on Middle and West Island may limitsecondary poisoning because only a limited partof the island would be treated at any one point intime.

…__________________________________________________________________

Figure 14. Risk quotients (RQ ) for 500-1000 g birds

1.61

0.13 0.010

0.80

0.06 0.0050.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

25Brodifacoum

50Bromadialone

50Diphacinone


RQ

Theoretical Maximum

Theoretical Minimum

EPA LOC (0.5)


CHAPTER FOUR - 73

The risk of secondary poisoning topredators/scavengers of rats and mice is limitedby the availability of these prey in space andtime. For the aerial predators on Anacapa, theirsearch image is for live prey and thus risk ofpoisoning is during the latent period (after ratsand mice have consumed the bait, but have notyet died) (estimated at 2 weeks). Anticoagulatedpoisoned rats and mice could be available toboth diurnal and nocturnal predators andscavengers. On Anacapa, islet wide treatmentwould yield numerous dying rats and micedisplaying erratic behavior and likely would be asignificant prey base because of the ease ofcatching them. Similarly, a number of rats andmice would die above ground and available fordiurnal scavengers. There would be extensivesecondary poisoning of the birds of prey withthe use of brodifacoum or bromadiolone. Therisk of secondary poisoning would besignificantly less, although present with the useof diphacinone.

Mitigation

It is recognized that the landbirds are at risk ofprimary and secondary poisoning. To minimizevisual attractiveness to birds, and thus primaryexposure, the bait would be dyed blue or green;colors known to be less preferred by thePasserines. Suggested mitigation measures tominimize or prevent exposure to the rodenticidescould include: Live trap and release owls anddiurnal birds of prey on the mainland, or livetrap, hold in captivity until the risk periodpasses, and release birds of prey back on toisland.

This mitigation would be difficult toimplement because live trapping of specificindividual birds can be difficult if not impossible(B. Walton, pers. comm., G. Howald, pers.obs.). If required to implement, efforts would bemade, but no guarantees that all individualswould be removed. Similarly, removal of birdsof prey from Anacapa, could result in more birdsfilling the empty territories potentiallypresenting a greater secondary poisoning riskbecause more birds would be present (B.Walton, pers. comm.).

An alternative approach may be to provide

Table 16. Occurrence of landbirds inthe Channel Islands National Park andtheir foraging strategies.

Island Gra

nivo

re

Om

nivo

re

Inse

ctiv

ore

Car

nivo

re

Tot

alAI 3 3

SBI 1 13 5 4 23

AI andSBI

3 53 14 8 78

OtherIslands

9 2 3 14

Total 4 78 21 15 118

______________________________

Table 17. The birds of prey and scavengers ofAnacapa Island at risk of secondary exposure

Birds of Prey Scavengers

Barn Owls

Burrowing Owls

Short-eared Owls

American Kestrel

Northern Harrier

Red-tailed Hawk

Common Raven

American Kestrel

_________________________________________


CHAPTER FOUR - 74

the landbirds with supplemental food whichwould be more attractive than the bait pelletsand/or rodent carcasses. Supplemental feedingstations would have to be established andregularly maintained before, during and after thebaiting period.

For those carnivorous species that wouldscavenge dead rodents, carcass searching couldbe carried out to find, collect and dispose of anydead rodents. Thus, secondary exposure viacarcasses is minimized.

Sub-Issue 7 – Terrestrial MammalsPrimary Exposure (Direct)

Toxicology - Acute oral toxicity data existsfor mammals (Table 18). Brodifacoum is themost toxic rodenticide proposed under thealternatives.

Bait Composition, Delivery and Behavior -The presence of the deer mouse on AnacapaIsland presents difficulties for eradication.

The baits are optimized for rodent control,and subsequently mice would be attracted to andwould consume the bait. The impact on themouse population would be heavy. The aerialbroadcast of bait into the ecosystem increasesthe probability that any one individual mousewould be exposed to the bait, however, theexposure would be limited to a short window intime as bait would be removed from territories.However, it may not result in 100% mortalitybecause rats have larger home ranges than mice(Howald et al. 1997) and are competitivelydominant. Consequently, it can be difficult tosimultaneously eradicate both species becausethe rats consume all the bait before the micehave access to it. If all the bait is consumedwithin the home range of an individual mouse,that mouse would then escape contact with bait(D. Veitch, pers. comm.). If on Anacapa, ratsconsume all the bait within an area larger thanthe home ranges of male deer mice on AnacapaIsland (Howald et al. 1997), then the mice living

in those areas would likely survive for sometime without contacting bait.

The RQ indicates that brodifacoum andbromadiolone exceed the EPA Level of Concernof 0.5 (Figure 15). Diphacinone offers someprotection to deer mice, assuming that the LD50

for house mice is representative of the sensitivityof deer mice. Deer mice are at a high risk ofpoisoning after a single days feed on baitcontaining either brodifacoum or bromadiolone.

There would be a high impact to the mousepopulation.

Secondary Exposure (Indirect)The risk of secondary exposure to mice is

believed to be small. The only route of exposurewould be through the ingestion of aninvertebrate containing rodenticide residues, orthrough consumption of poisoned carrion. Thelow retention time of the rodenticides ininvertebrates limits this exposure window.Alternatives 2, 4, and 6 would limit the temporalrisk. Bait stations in the remaining alternativeswould increase the probability of secondaryexposure over time.

MitigationThe endemic subspecies of the deer mouse

on Anacapa represents a logistical challenge toeradication of rats. The proposed mitigation formice is outlined in Chapter 2.

Cumulative EffectsThis section will analyze how each of the

alternatives could have a cumulative impact topredators and scavengers through repeatedexposures to the rodenticides, and the potential(non-toxicological) cumulative impacts toseabirds. Included is a summary of rodenticidetoxicology issues from the Mainland of SouthernCalifornia which could contribute to non-targetimpacts.


CHAPTER FOUR - 75

Alternative 1 – No ActionThis alternative would utilize no

rodenticides and therefore would have nopotential for cumulative exposures.

Effects Common to Alternatives 2, 3, 4, 5and 6The use of brodifacoum or bromadiolone couldresult in predators and scavengers being exposedto the rodenticides through cumulativeexposures. The properties of these chemicals(outlined above) are such that they are relativelyinsensitive to metabolism in vertebrate tissuewhich could result in accumulation of residuesin time. The consequence of re-exposure isdetermined by how long after the initialapplication the bait is re-applied, the amount ofarea re-treated and the rodenticide in the bait.The 20 ha headland of Middle Island is not

anticipated to be re-treated for up to a year afterinitial application. However, there may be arequirement for the re-treatment to protect EastIsland intermittently through the year. Anyother areas treated initially would not be re-treated between one and two years after theinitial application. This analysis is divided intoprimary and secondary exposure.

Middle Island Headland Re-Treatment

Primary ExposureBetween each treatment, there will be enoughtime elapsed for degradation of any residual baitthat may not have been consumed by the rats ormice, thus reducing primary risks betweentreatments to very low or negligible. Thisnegligible period is expected to carry throughthe landbird breeding season, thus allowing birdsto successfully breed before re-treatment may be

Table 18. Acute Oral Toxicity of Rodenticides to Mammals (LD50 mg/kg) (A dash indicates that no data isavailable) (adapted from Erickson 1999)


SpeciesBrodifacoum

Alternative 2, 3 and 6LD50

BromadioloneAlternative 4 and 5

LD50

DiphacinoneAlternative 6

LD50

Norway Rat 0.26-0.56 0.56-0.84 2.3-7.0

Black Rat 0.65 a - -

Laboratory Mouse 0.4 1.75 50-300

Vole 0.2 - -

Dog 0.25-1.0 10-15 0.88-7.5

Coyote - - 0.6

Rabbit 0.29 1.0 35

Guinea Pig 2.78 2.8 -

Mink 9.2 - -

Mongoose - - 0.2

Cat 25 - 14.7

a from Taylor 1993


CHAPTER FOUR - 76

necessary. As the rat population grows, and ifthey re-invade the headland, and the risk of re-invading East Island is deemed to be high, thetreatment of the headland may be required.Thus, after treatment the primary poisoning riskwould again be high, but not as high during theinitial application because fewer rats wouldlikely be occupying the territory and thus wouldnot require as high a sowing rate to kill them all.The application period may cross over into theWestern Gull breeding season and may result inprimary exposure of gulls to the rodenticide.During the spring 2000 field trials, placebo bait,was not found to be attractive to gulls occupyingnesting territories. This data suggests thatalthough some gulls may be attracted to andconsume bait, there will likely not be extensiveprimary exposure of gulls.

Secondary ExposureThe risk of secondary exposure would be greatestduring the initial application, and less with thesubsequent re-applications because fewer rats andmice would be available as prey and there wouldbe less bait placed into the environment.Similarly, if baiting of the headland occurs duringthe gull breeding season, there would be lessoverall risks to birds of prey on the islandsbecause gulls harass the raptors generallyexcluding them from the island. During the springand summer periods, very few, if any, birds ofprey were observed and they were not detectedduring bird surveys. Some species, such as theBurrowing Owl and Short-eared Owl onlyoverwinter on Anacapa Island, thus, they wouldnot be present during the intervening monthswhen the headland on Middle Island would betreated, thus escaping re-exposure. However,

Figure 15. Risk Quotient (RQ) for a 20 g deer mouse.

10.51

4.81

0.17

0.00

2.00

4.00

6.00

8.00

10.00

12.00

25Brodifacoum

50Bromadialone

50Diphacinone


RQ

EPA LOC (0.5)


CHAPTER FOUR - 77

upon return to the islands, they may be at a greaterrisk of being lethally exposed to the rodenticide ifthey already contain sub-lethal levels ofrodenticide residue in their tissues from exposureon the mainland. In other words, individuals couldsuccumb to smaller and smaller amounts ofrodenticides because of the sub-lethal levels intheir tissues. This situation would be dependenton the availability of the rodenticide residues intime on the island. Re-application of an areacould result in rodenticide residue being availablein time which could lead to cumulative exposure.

Kaukeinen (1982) reported that nosignificant wildlife mortalities have beendocumented after 30 years of anticoagulantusage. Thus, the consequence of baiting wouldbe restricted to non-target species that would befound on Anacapa Island. Migratory speciesthat overwinter on Anacapa Island couldpotentially be exposed to the rodenticides onAnacapa, survive, and on return to breedinggrounds on Mainland California, be exposed tothe rodenticide and could succumb to therodenticide exposure. The anticoagulantrodenticides have been detected in wildlifelosses on Mainland California (B. Hosea, pers.comm.) and recently in golden eagles trapped onSanta Cruz Island (T. Coonan, pers. comm.).The detection of brodifacoum in golden eagleson the islands indicates that species with sub-lethal levels of rodenticide are transporting thechemical into the Channel Islands National Parkfrom the mainland since no vertebrate pestcontrol has taken place. With residues in theirtissues they could be re-exposed to theanticoagulants on Anacapa Island, and succumb.The golden eagles are non-native species to theislands and are currently being removed fromthe islands (3-5 total remain). Only one goldeneagle has been observed around East AnacapaIsland (ICEG 2000). As time passes, the relativeexposure risk would decline because limited baitwould be applied in a relatively small area ofland, at one point in time. On the mainland, therodenticides are used for control and follow a

chronic use pattern extensively around the statein both agricultural and urban settings.

Alternative 6The use of diphacinone under alternative 6

could represent a risk of poisoning to non-targetspecies via the mechanism outlined above. Therelative risk would be less than brodifacoum orbromadiolone because of the significantly lowerresidence time in vertebrate tissue.

SeabirdsThis project objective is to restore the island

and as a consequence, free up seabird nestinghabitat. Pressures on the seabird populationsthat utilize or could utilize Anacapa Island forbreeding include oil spills and the squid fishery.The squid boats fish at night with high poweredlights to draw in the squid for harvesting. Thelight boats cause increased predation to theadults and juvenile seabirds, and are known tonegatively influence normal breeding activities(B. McIver, pers. comm.). Oil spills cause oilingof feathers which negates the insulatoryproperties of the feathers and leads tohypothermia and death. This section of theanalysis will evaluate the cumulative effects toseabirds for each alternative.

Alternative 1 – No ActionUnder this alternative, the negative impacts

of oil spills and light boat activities wouldcontinue. Together with the presence of the ratson Anacapa Island, the reproductive potential ofthe seabird population would be seriouslyhindered.

Effects Common to Alternatives 2-6Under these alternatives, rats would be removedfrom the island. The removal of the rats fromthe island should result in an increase inseabirds, particularly the Xantus’ murrelet. Theincreased population could help offset some of


CHAPTER FOUR - 78

the negative impacts from both oil spills andsquid fishing. For example, if during thebreeding season and the Xantus’ murrelets werebreeding in large numbers on both Anacapa andSanta Barbara, and a large oil spill occurredaround either island, only one of the twopopulations of birds may be at risk of oiling(under the broad assumption that eachpopulation has a distinct foraging range awayfrom each other). Compare with the occurrenceof an oil spill around Santa Barbara Island,where a significant portion of the breedingpopulation is at risk of oiling if rats were notremoved from Anacapa. Similarly, theincreased population of birds could help offsetthe potential impacts from predation due to lightboats around the island. However, the presenceof the light boats may also have a detrimentalimpact on the seabirds such that the seabirdpopulation could not grow even with the ratsremoved.

Issue 3: Public Safety andVisitation

IntroductionThis section in the analysis will analyze the

potential exposure of the general public to therodenticides and how the proposed action wouldpotentially impact visitors enjoyment to the parkduring the baiting operations. Within theexposure to the rodenticide section, the analysiswill discuss how each method of delivery of therodenticide may expose the visiting public to therodenticide and associated health risks ofexposure. Within visitor impacts, the effectsdiscussion will focus on how the alternativescould potentially impact enjoyment of the parkduring operations.

Exposure to the rodenticideThe different application methods of the

rodenticides could potentially expose the visitingpublic to the rodenticide through primaryexposure. However, it should be noted that thiswould need to be an intentional exposure on thepart of the visitor, i.e., a person would have toseek out the bait and deliberately consume it.Anacapa Island is open to the visiting publicyear round. Visitors are allowed access to EastIsland and with permission, to West Island inFrenchy’s Cove. Thus, primary exposure to therodenticide is limited to these areas of the island.There is a small possibility that fisherman maycatch fish that could contain trace amounts ofrodenticide residue, thus, being secondarilyexposed. This analysis is organized byapplication technique (aerial vs. bait station). Asummary analysis outlining the health concernsassociated with exposure is presented.

Aerial Broadcast (Alternatives 2, 3,4, 5, and 6)

Each of the alternatives would use aerialbroadcast either on the cliffsides or both thecliffsides and top of Middle and East Islands.The aerial broadcast of a rodenticide baitincreases the probability that a bait is found inany one location on the treated area. However,the probability of finding a bait pellet would besmall. Bait pellets are about 2 g in size, andwould fall to the ground with enough force to becovered by vegetation and out of general sight.

The alternatives would restrict public accessto the island 2-3 days during treatment. Thisclosure period would allow for the rats and miceto consume the majority of the bait within 72hours (ICEG 2000). The buffer areas around thebuildings and campground on East Island wouldnot be aerially treated, thus reducing theprobability of finding the bait pellets even furtherbecause these areas attract the greatest number ofvisitors. Signs posted at the landing areasindicating that the island has been treated would


CHAPTER FOUR - 79

provide information about the program to visitorsand warnings about the bait and to avoid it ifencountered.

There is a risk of bait pellets drifting into themarine environment from aerial activity. The baitpellets may be consumed by fish and potentiallyrepresenting a secondary poisoning hazard tofisherman consuming the catch. The likelihood ofexposure is small, and significant exposure viathis pathway is believed to be even smaller. Thefish population studied did not consume any baitpellets, although sheephead was noted to chewand spit out the bait. The amount of residuesfound within the consumable flesh of fish wouldlikely be of inconsequence relative to the amountrequired for measurable effects (Table 19). Onlyfish around Anacapa could be exposed to the bait,and of those only in the nearshore waters. Thereis a fishing restriction to 60 ft depth around thenorth shore of Anacapa, lowering the probabilityof rodenticide exposure to fisherman even further.

Bait Stations (Alternatives 3 and 5)In these alternatives, the use of bait stations

around the buildings and campground on EastIsland would limit the potential for exposure tothe rodenticides. The rodent bait would beencased within a lockable station that would beappropriately labeled “Rat Poison- Do NotDisturb”. Pesticide labels attached to the

stations would provide information as to the baitin the stations and emergency contact numberswould be provided as well as treatment forexposure. The stations would limit access to thebait to all but the most persistent visitors, suchas those that may vandalize stations.

Consequence of ExposureThe exposure to small amounts of the bait is

considered to present a very low risk to humans.Warfarin, a relative of brodifacoum andbromadiolone, is a common antithrombinmedication, administered to human patients as adrug to “thin” the blood preventing heart attacksand strokes. If sufficient amounts are consumed,exposure to either of the rodenticides wouldhave the same effect as warfarin. In effect,“thinning” the blood. If too much wasconsumed, an antidote would be available.Treatment is through dietary or daily injectionsof Vitamin K1, a common and readily availablevitamin. Studies have shown that workershandling brodifacoum, the most potent of thethree rodenticides presented, over a 9 monthperiod did not show any effects suggestive ofsignificant exposure (ICI, in Taylor 1993).

To demonstrate the relative risks ofexposure, the number of 2 g bait pellets required

Table 19. Number of bait pellets for one LD50 exposure to humans for each rodenticide a

Age Weight (kg) Brodifacoum Bromadiolone Diphacinone

Adult 70 364 392 1610

Child 10 52 56 230

a LD50 defined as amount of pellets required for a 50% chance of lethal hemorrhaging . LD50 assumed to be 0.26 mg/kg forbrodifacoum, 0.56 mg/kg for bromadiolone and 2.3 mg/kg for diphacinone, based on LD50 data for the Norway rat.

_________________________________________________________________________________________


CHAPTER FOUR - 80

to consume one LD50 for an adult and child ispresented (Table 19).

SummaryThe probability of visitors exposed to the

bait is extremely small. The probability ofexposure would be limited by closing the islandfor 2 –3 days, allowing for the vast majority ofthe bait to be cleaned up by rats and mice.Posters would warn visitors of the application,and bait stations around buildings with pesticidewarning labels. Additionally, it would be ratherdifficult for one to find and consume enoughbait to be of any consequence. Effectivemedical treatment would be available because ofthe slow onset of toxicosis and availability of anantidote (Vitamin K1).

MitigationThe bait could contain a bittering agent

(bitrex) at a concentration known to deter humanconsumption, yet still be highly attractive to rats.However, there are data which suggest thatbitrex could have a detrimental impact oneradications because some rats may be sensitiveto the bittering agent (D. Veitch, B. Simmons,pers. comm.). The bait would be dyed a blue orgreen color that may be diluted out of the baitwhen exposed to water such as saliva and /orsweat making it a good indicator for someonewho may have incidentally eaten or picked upthe bait. Hospitals would be notified prior to theoperation that anticoagulants have been used,and to not overlook symptoms of anticoagulantexposure.

Public areas on East Anacapa Island – trails,picnic areas and campgrounds would beinspected for any exposed bait, which would beremoved before the island is open to the public.All employees and other park staff would beinstructed about any hazards concerning therodenticide before they are allowed on the islandafter application.

Impacts to Visitor EnjoymentVisitation to Anacapa Island is highest in the

summer and lowest in the fall and winterperiods. November and December are theslowest months with relatively minor numbersof visitors to the islands as compared to the peakseason (Figure 16). The project plan would beto divide the islands into two sections, treatingEast Anacapa Island in year one and thenMiddle and West Island in year 2, thus alwaysleaving one of the two public areas open tovisitors at any one point in time. Similarly, theother Park islands would be open to visitorsthroughout the project period. Therefore,closure of the island for 2-3 day period postapplication would have no significant impact tovisitor enjoyment.

Figure 16. Visitor use during proposed treatmentperiod.

0

2000

4000

6000

8000

10000

12000

14000

16000

Avg

Ann

ual V

isito

r Use

(96-

99)

96-99 Sum ofAverage Visitor UseJan-Sept,December (90% ofTotal)96-99 Sum ofAverage Visitor UseOct & Nov (10% ofTotal)


CHAPTER FOUR - 81

Sustainability and LongTerm Management

This section of the analysis will focus inon the relationship between local short-term usesof the environment and the maintenance andenhancement of long term productivity,irreversible and irretrievable commitments ofresources, and adverse impacts that cannot beavoided. The analysis is divided into the noaction alternative and rats eradicated(Alternatives 2-6) since the impacts across allalternatives will be similar. The differencebetween the alternatives would be the scale ofimpact to the resources.

Relationship between Local Short-term uses ofthe Environment and the Maintenance andEnhancement of Long-Term Productivity

Alternative 1 – No ActionUnder this alternative, no short term uses of theAnacapa environment would take place. TheIsland would continue with normal Parkoperations as it has in the past. As a result, therewould be no new existing short-term uses thatwould affect long term productivity.

Alternatives 2-6 – Rats EradicatedUnder these alternatives, rats would be removedfrom the islands with the use of a rodenticide.The alternatives differ by rodenticide choice,intensity, and duration of application, however,the end result – rats eradicated - remains thesame. The use of the rodenticides in theAnacapa ecosystem represents a risk of non-target poisoning to birds and mice causingreductions in population sizes. However, theactions would be of short duration which wouldresult in short term declines of some species butthose species would recover. Mitigationmeasures to minimize those impacts have beendeveloped for landbirds. Deer mice have been

appropriately protected from extirpation orextinction as outlined in Chapter 2. The benefitof rat eradication would be the recovery of thenesting seabirds, increased mouse populations,increased populations of intertidal invertebratesand terrestrial invertebrates. This increase innative species populations could potentiallysupport greater numbers of those species thatwere incidentally poisoned with the rodenticide.In other words, the benefits outweigh the costs.

Irreversible and Irretrievable Commitments ofResources

The irreversible commitments are those whichcannot be reversed, except perhaps in theextreme long term . An example, extinction of aspecies is an irreversible loss. Irretrievablecommitments are those that are lost for a periodof time, e.g., restriction of visitor use while anarea is temporarily closed would be an ongoingirretrievable loss. The following describesirreversible and irretrievable commitments ofresources resulting from affirmative actionsidentified in the various alternatives.

Alternative 1 – No ActionUnder this alternative, continued rat predation ofseabirds would represent an irretrievable loss.An irreversible loss could be the lack ofregeneration of the island oaks and cherries onWest Island. Similarly, the financialcommitment of the American Trader TrustCouncil would be an irreversible loss since thefunds are dedicated towards seabird habitatrestoration.

Alternatives 2-6 – Rats EradicatedUnder each of the alternatives there would be noirreversible loss of resources. There would beirretrievable loss of resources, in particular, miceand landbirds. However, these resources areproposed for mitigation and protection beforethe operations would begin.


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Unavoidable Adverse ImpactsThe impacts identified below for eachalternative are those for which there are nomitigating measures or which could not bemitigated to a level of insignificance.

Alternative 1 – No ActionThe No Action alternative, by definition,contains no measures to mitigate impacts toresources. The presence of rats in the Anacapaecosystem will continue to result in significant,unmitigated, adverse impacts to seabirds,landbirds, mice, invertebrates, and plants.

Alternative 2-6 – Rats EradicatedUnder each of the alternatives, the level ofmitigation should be sufficient for a level ofinsignificance.


CHAPTER FIVE- 83

........


Chapter one

CHAPTER FIVECONSULTATION AND COORDINATION

Need

Chapter Contents

COORDINATION ........................................................................................................................ 84

PUBLIC INVOLVEMENT........................................................................................................... 84INTERNAL SCOPING...............................................................................................................................84EXTERNAL SCOPING .............................................................................................................................84

LIST OF PREPARERS................................................................................................................. 85

LIST OF RECIPIENTS................................................................................................................. 86

RESPONSE TO COMMENTS..................................................................................................... 87

DEIS RESPONSE TO COMMENTS……………………………………………………………87


CHAPTER FIVE - 84

Coordination

Although Channel Islands National Park hasidentified Anacapa Island rat eradication as apriority for management with its inclusion in the1985 GMP, it was not until the IslandConservation and Ecology Group (ICEG)submitted a rat eradication proposal (Tershey et.al 1997) to the Park that a specific action wasdeveloped.

Because the primary benefactors of rateradication on Anacapa Island are seabirds, thePark found support for the planning of theproject through the American Traders TrusteeCouncil (ATTC). The ATTC was formed as aresult of an oil spill off of the Huntington Beachshore from the single-hull tanker AmericanTrader in 1990. The ATTC is responsible forthe dissemination of settlement monies paid bythe oil carrier.

The ATTC was able to support the restorationplanning for this project because the proposedactivity primarily benefits seabirds and seabirdhabitat. Monetary support of the planning of thisproject was disseminated through a cooperativeagreement between ATTC, NPS, and ICEG. Thecooperative agreement outlined responsibilities ofeach party during the planning phase of thisproject. The Park will seek funding throughATTC to implement the decision that results fromthis analysis.

Public Involvement

The NEPA “scoping” process [40CFR1501.7] was used to determine the scope of theanalysis and to identify potential issues andopportunities related to the Proposed Action. A

summary of the scoping and public involvementprocess for the proposed project is as follows:

Internal ScopingThe Park has an extensive record of

controlling rats on EAI. Through these efforts,the Park has collectively gained knowledgeabout the issues surrounding the presence of ratson the island. In addition, the Park has fundedscientific studies that focus on the ecology andcontrol of rats within the Park.

External ScopingIsland Conservation and EcologyGroup(ICEG)

ICEG is a non-profit conservation groupmade up of American and Mexican conservationbiologists, educators, and public officials workingto protect biological communities on the over 250islands in northwest Mexico and California.Since 1996, ICEG biologists have been studyingthe rat infestation on Anacapa Island and haveadvised the Park on ecological issues associatedwith rats on the island.

Vertebrate Pest ExpertsAs part of the Vertebrate Pest Conference

held in San Diego, CA (3/6-9, 2000) vertebratepest experts made a site visit to Anacapa Islandto discuss the rat eradication project. Theircomments and concerns were recorded andhave been considered in this analysis.

General Public and GovernmentRegulatory Agencies

The Park has made extensive efforts toinform and seek input from the general publicand government regulatory agencies regardingthe need to eradicate rats from Anacapa Island.These efforts include the following:


CHAPTER FIVE - 85

� 11/18/99 - Scoping letter sent to allinterested publics who expressed an interestin Channel Islands National Park. Thisincluded all government regulatory agenciesthat may have oversight authority regardingthe proposed action.

� 11/19/1999 – Park press release sent to alllocal media outlets. This resulted in storiesregarding the proposed project in three localnewspapers (Ventura Co. Star, SantaBarbara Newspress, and LA Times).Several out of area newspapers printed thearticle when the Associated Press distributedit on its AP wire. A Santa Barbara local TVstation (Channel 6 KSBY) aired a storyregarding the proposed project.

� 11/20/1999 – Park posted information on itsWorld Wide Web (www) site. Thisincluded a Frequently Asked Question(FAQ) summary regarding this project.

� 11/26/1999 – Notice of Intent (NOI) toprepare and Environmental ImpactStatement for this project was published inthe Federal Register.

� 12/8/1999 – Public meeting held at the Park.Paid for ads and public notices announcingthe meeting were published in three localnewspapers (Santa Barbara Free Press,Ventura County Star, and the Los AngelesTimes). A local radio station (KVEN 1520)covered the meeting and aired its story thefollowing day.

� 7/7/2000 - Notice of Availability for theDraft EIS appeared in the Federal Register.Combined, the Park widely distributed papercopies or CD-ROM disks to over 100government agencies, organizations, andindividuals. In addition, the DEIS was madeavailable on the Park’s website. The Parkalso issued a press release to 50 local mediaoutlets announcing the release of the DEIS.This resulted in at least two articles about

the project and the release of DEIS forcomments (Santa Barbara Free Press and theLA Times).

� 9/5/2000 – This date ended the reviewperiod for the DEIS. At the end of thischapter is the Park’s response to thesubstantive comments that were sentregarding the DEIS. Included is a fullreprint of the letters the Park received on theDEIS.

List of Preparers

FEIS Preparation

Steve Ortega RestorationSpecialist

ChannelIslandsNational Park

GreggHowald

WildlifeBiologist[Ecotoxicology]

IslandConservationand EcologyGroup

FEIS ReviewKateFaulkner

Natural ResourcesDivision Chief


TimCoonan

Branch Chief forTerrestrialMonitoring andRestoration


AllenSchmierer

EnvironmentalComplianceSpecialist

Pacific WestRegion –National ParkService


CHAPTER FIVE - 86

FEIS Technical AssistanceCathy Schwemm GIS

SpecialistChannelIslandsNational Park

List of Recipients

Below is a list of all agencies, organizations,and individuals that will receive a copy of theFEIS.

In addition, the Park will notify the generalpublic that the FEIS is available for commentby:

• Issuing a press release to the 50+ localmedia outlets that are part of the Park’sPublic Relations mailing list

• Placement of a legal notice in both theSanta Barbara News Press and theVentura County Star

• Post the FEIS on the Park’s website inPDF format

Government• California Department of Fish & Game• U.S. Fish and Wildlife Service (Ventura

Office)• Environmental Protection Agency

(Washington Office)• California Environmental Protection Agency• Central Coast Regional Water Quality

Control Board• California Coastal Commission• National Marine Fisheries Service• Channel Islands National Marine Sanctuary• U.S. Army Corps of Engineers• U.S. Geological Survey• Canadian Wildlife Service• U.S. Coast Guard• National Wildlife Research Center, U.S.

Department of Agriculture• Honorable Lois Capps

• Honorable Elton Gallegly• City of Ventura

Organizations and Businesses• Santa Barbara Museum of Natural History• National Wildlife Research Center• Institute for Wildlife Studies• The Nature Conservancy• Santa Barbara Botanic Garden• Catalina Island Conservancy• Environmental Defense Center• National Parks and Conservation

Association• California Native Plant Society• National Fish and Wildlife Federation• Pacific Seabird Group• American Trader Trustee Council• Island Packers• National Audubon Society, Seabird

Restoration Program• Ventura Audubon Society• Santa Cruz Island Foundation

Individuals• Peter Triem• Bruce Colvin• Gillian Keys• Deborah Jaques• Charles Drost• Desley Whisson• Frank Gress• Dan Anderson• Lyndal Laughrin• William Everett• Dick Veitch• Buck Hull• Ole Barre• Jack Gillooly• Eiji Imamaura• Steve Junak• Cristina Bren• John Cloud• Scott Cooper• Jack Engle• John Gherini• Tom Gherini


CHAPTER FIVE - 87

• Michael A. Glassow• Jeff Howarth• Julie Tumamait-Stensile• Adrian M. Wenner

The Park maintains a mailing list ofindividuals and organizations interested in theactivities of Channel Islands National Park. Anotice will be sent to this mailing list thatnotifies them of the availability of the FEIS.The notice will give instructions on how torequest a copy of the FEIS or view it at thePark’s website.

Response to ScopingComments

At the public meeting comments were givenregarding the project. In addition, the Parkreceived five written comments on the proposal.The comments received on the proposal wereeither asking the Park to consider a certainalternative, or to consider certain impacts whichmay occur as a result of implementing theproposed action.

AlternativesThree alternatives were recommended

during the scoping period:

• Introduce predatory snakes• Introduce neutered/spayed cats from animal

shelters• Use less toxic rodenticides

Each of these alternatives are discussed inChapter II. The use of less toxic rodenticideswas an alternative put forth to address the issueof non-target species poisoning. The issue ofnon-target species poisoning is discussed inChapter IV Environmental Consequences.

ImpactsThe comments the Park received on

potential impacts to wildlife species asked that

the analysis include impact analysis for thefollowing species:

• Raptors

• Anacapa Deer Mouse

• Pinnipeds

The Environmental Consequences section inChapter Four address impacts to these speciesand others.

DEIS Comments andResponses

The following are letters that were receivedon the DEIS and the Park’s response to thecomments.

A1: The impacts to invertebrates has been adequately described (p. 66) for variousspecies. Invertebrates do not have a Vitamin K dependent blood clotting system andtherefore are not believed to be negatively impacted by the anticoagulantrodenticides.

Landbirds: The risk analysis for landbirds evaluated the potential for primary andsecondary exposure (p. 69). The risk analysis grouped landbirds primarily byforaging strategy which is the primary risk evaluation tool as it determines risk ofprimary or secondary hazards. Included was a summary of studies completed thatdocumented no landbirds were interested in placebo bait pellets presented. There areno landbirds endemic to Anacapa Island, however, there are endemic subspecies thatexist on Anacapa and the other much larger and diverse Park islands (San Miguel,Santa Rosa, and Santa Cruz Islands) and the other Channel Islands (Diamond andJones 1980, Johnson 1972). Of the eight endemic avifauna found on Anacapa, all arealso found on at least one or all of the Channel Islands. Adequate mitigation, suchas timing of operation, color of bait pellets, size of bait pellets and formulation of baitpellets will be adopted to minimize risk of rodenticide exposure.

A2: All acute toxicity data is presented in the EIS. No toxicity data exists for manyspecies found on Anacapa Island. For risk evaluation, it is common practice by theUS EPA to utilize data from species representative of specific groups eg., Passerines,upland gamebird, and waterfowl. It is impossible to predict the response of anyspecies to a pesticide without data from that species. It is logistically and financiallyinfeasible to collect laboratory toxicology data on every individual species. The datapresented allows an evaluation of the relative risks. Wherever possible, we utilizedstatistical data from the literature that more accurately estimated the acute toxicity ofthe rodenticides to birds. The data presented then allows for inferences to be drawnabout the relative risks and response that could be expected.

A3: The AIRP focuses on restoring seabird nesting habitat. The benefits extend notonly to seabirds, but also to landbirds, the Deer Mouse, invertebrates (terrestrial andmarine), and plants through relief from predation pressure from rats. Rats onAnacapa Island have altered the ecosystem and are responsible for extirpatingseabirds and other species from the island (eg. the 20 year absence of the DeerMouse from East Anacapa Island). Worldwide, introduced rats appear to beresponsible for about 50% of all bird and reptile extinctions. Anacapa Island may bea “sink” to many species because of the presence of rats. Some species are likelykept at a chronically low level, presenting a risk of susceptibility to environmentalchanges. The removal of rats will greatly benefit these groups of species. There areno endemic species, except for the Deer Mouse, on Anacapa Island that are at risk ofrodenticide exposure. All impacted species will likely recover to pre-eradicationlevels or greater. For those species that are being heavily impacted by rats (seabirds,landbirds, invertebrates), their numbers will increase rapidly post eradication, andlikely will exceed the pre-eradication levels. (continued next page)

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LETTER A: VENTURA AUDUBON SOCIETY

A3 continued: The susceptibility to the rodenticide, followed by a recovery to levelshigher than measured pre-eradication has been documented in New Zealand andelsewhere after rat eradication. The benefit of the eradication clearly outweighs therisk of rodenticide exposure.

A4: A discussion of persistence requires an analysis of the temporal and spatialavailability of the rodenticide. The temporal availability of the rodenticides has beendiscussed on pages 61 and 64. The spatial availability of the rodenticide is onlyrelevant if it is available to be consumed/absorbed by a biological organismsusceptible to the chemical. Any residual bait that is not degraded due to rainfall, orheavy moisture will be susceptible to microbial degradation. There are no toxicmetabolites. The rodenticide itself will bind strongly to organic matter in the soilwhere microbial degradation will expedite the detoxification process reducing therodenticide to its base components of carbon dioxide and water. The binding to soilwill lock the rodenticide, making it biologically unavailable to birds and mice. In thevery extreme case of bait entering and residing unconsumed in a dry location on theisland, the bait will still be susceptible to microbial degradation. There will not beany bait available in dry locations to be of biological significance to any population.These dry habitats, such as caves, are also good habitat for rat and mouse burrowsand any bait found in these areas will likely be the first pellets to be consumed.

A5: The analysis focussed on primary and secondary poisoning. Tertiary poisoning ispossible; however, very little study has been reported in the scientific literature. Studieshave documented that invertebrates consuming the bait will test positive for therodenticide so long as the bait is present in the gut of the organism. No rodenticideresidue will likely be bound within invertebrates once the bait is excreted, thus,presenting a very low risk of moving the rodenticide into the food chain over the longterm. The rodenticides appear to not persist in invertebrate tissue(Pain et al. 2000).

A6: The known ecotoxicology data for herpetofauna was presented in the EIS (pg. 67).There are plans to monitor the herpetofauna population to evaluate the potentialtoxicological effects. Although there may be some impacts to herpetofauna, there isevidence to suggest that removal of rats will cause increase in the herp population tolevels higher than pre-eradication (Merton 1987). Rats are known to prey on theherpetofauna of Anacapa Island and the population may be chronically suppressedbecause of the rats. In other words, it is expected that the herpetofauna population willrebound and increase to levels higher than currently found on Anacapa Island.

(Continued next page)

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LETTER A: VENTURA AUDUBON SOCIETY CONT.

A7: Rats prey on the Anacapa Deer Mouse and were believed to be responsible for the 20 year extirpation of the Deer Mouse from East Anacapa Island. Rats preyed on and outcompeted the mice for resources on the island. The bait, formulated for rodents, will be highly palatable to both the rats and mice. Rats will be competitively dominant for the resource.Sowing rates have been optimized such that very little if any bait will be remaining after application and once rats and mice have removed the bait.

A8: Although pelicans may be roosting on the island during the non-breeding season, it is anticipated that the pelicans may temporarily use alternate roost sites on other islandsduring the period of helicopter activity. There will be no direct effect of the rodenticide bait on the pelicans since they are fish eaters. There is no likelihood that they will ingestany bait directly, or secondarily from contaminated prey. The bait will be in a pellet form and is not expected to adhere to bird feet or feathers, therefore, it is unlikely that pelicanswill inadvertently ingest the pellets during preening activities. Pelicans are not scavengers and will not eat dead and poisoned rodents. (It is expected that most (87-100%) ofrodents will die underground after consuming the bait.) Pelican prey species are schooling fish such as anchovies and sardines, species which will not come into contact with thebait.

A9: The reasons for the methodology have been outlined in Chapter Two. The reasons for not pursuing placement of bait stations across the whole island are described on page26.

The hand placement of baits from above and below, alone would not accomplish the purpose and need. Hand distribution of bait would not meet the basic requirement that bait bedelivered in every rat’s territory. Personnel would be required to stand precipitously close to the edge of the cliff. The cliff edges are extremely unstable and present a significanthazard to personnel. Daily orientation visits for visitors to Anacapa include a discussion of the necessity of avoidance of cliff edges because of the danger. Similarly, all clifffaces are not accessible. The cliffs rise 60 m to almost 300 m on West Island. There is no guarantee that by hand baiting, enough bait could be placed in high enoughconcentration on the cliff side to meet the purpose and need.

A10: Rats do exist on the offshore rocks (G. Howald, pers. obs.). The offshore rocks are close enough to the Anacapa Islands that rats could easily swim the distance to theisland. Thus, if the offshore rocks are not treated, there would be an unacceptably high risk of rats re-invading the island negating the investment in eradicating the rats.

Al1:Aerial application of rodenticides for rodent control to protect endemic and native birds is a tool being pursued in Hawaii. Island rat eradications using the aerial broadcast ofrodenticides have been carried out over many islands including in New Zealand and elsewhere in the world. The aerial broadcast of pesticides is common on agricultural lands onthe mainland in Southern California. The preferred aerial applicator is an experienced agricultural aerial pesticide applicator, certified by the State of California.

A12: The reason for not pursuing bait stations on Anacapa Island has been outlined on page 26. The relative risk of non-target exposure to the rodenticides would be less withbait stations, however, it is technologically infeasible to place bait stations on the cliffsides. Baiting the cliffsides is necessary to meet the purpose and need of the project.

A13: In May 2000, studies were initiated to evaluate if rats would cross the channel between East and Middle Island. Rats from Middle and East Island were live trapped, fittedwith a radio collar, and released in the channel, on the opposite island from which they were captured. After 3 months, no rat has been detected to cross the channel. Nonetheless,we recognize that rats re-invading East Island is a possibility. Re-invasion prevention is outlined in response D3.

A14: The Park fully understands the ecological implications of introductions of non-native plants and animals to Park islands. It is further understood that eradication should notbe pursued without a prevention program in place to keep re-introductions from occurring. The Park is committed to fully implementing all aspects of the prevention plan (asdescribed on pages 17) prior to the completion of rat eradication on Anacapa Island. Many aspects of the prevention plan, including public education and rodent proofing thePark’s departure points will be implemented prior to Fall, 2001.

A15: The purpose and need require that rats be eradicated from Anacapa Island. The preferred alternative offers the highest probability of successfully meeting the statedobjective. The use of a lesser toxic compound would result in a lower probability of achieving eradication. These lesser toxic compounds are valuable for control purposes, wherethey could be used chronically. However, control would require long term use of the rodenticides, which could result in greater impacts to non-target species than if the preferredaction were adopted in the first place. This project is proposing a one time use of the rodenticide, and would not require re-treating. There will be no long term deleterious effectsfrom the use of the rodenticide. Many species impacted by the rodenticide will rebound to pre-eradication levels and in some cases, exceed the levels found before eradication dueto release from rat predation.

A16: As written in the FEIS, ensuring the viability of the Anacapa Deer Mouse is a necessary action.

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LETTER A: VENTURA AUDUBON SOCIETY CONT.

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B1: Chapter Two (Alternatives Considered in Detail pgs 16) of the EISdescribes six alternative that are being considered for implementation. Eachalternative describes the toxicant and concentration, including the deliverymechanism. The inerts of the bait will be of a commercially manufacturedproduct, optimized for maximum palatibility and acceptance to rats.

B2: Chapter Five (Public Involvement pgs 84) describes the effort the Park hasmade to solicit public input on this project. Local newspapers (Ventura Co. Star,LA Times, and Santa Barbara Newspress) have published at least one featurearticle about the project, some have done two articles. The Park will continue tokeep the public informed via press releases, website, and public notices on thisproject as the compliance process moves forward.

The environmental analysis has discussed the potential human health risk and hasdetermined that exposure of visitors to the rodenticide is extremely low. Thisfact, along with the island closure and the information dissemination (asdescribed on pg 78) reduces even further the human health risk.

B3: The interaction between Deer Mice and Xantus’ Murrelets has beendescribed elsewhere (see Murray et al. 1983, Sydeman et al. 1998). The Xantus’Murrelet has evolved and contended with native predators such as mice on SantaBarbara Island (south of Anacapa Island) for centuries and is the largest breedingcolony in the USA. The Deer Mice prey only on eggs, while rats are capable ofpreying on eggs, chicks and adult murrelets severely impairing reproductivepotential in the short term and long term. Anacapa and Santa Barbara Islandshare similar habitats and the Deer Mice are the only native mammals on theislands. Rats are only found on Anacapa Island, which does not have asignificant murrelet breeding colony. (Continued on next page)

LETTER B: ENDANGERED SPECIES RECOVERY COUNCIL

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B3 Continued:

The abundance of available nesting habitat (McChesney et al. 2000),similarity to Santa Barbara Island, and presence of the Xantus’ Murreletattempting to utilize Anacapa Island for nesting, strongly suggests that theXantus’ Murrelet and other small, crevice nesting seabirds will benefitfrom the removal of rats. The removal of rats from Anacapa Island shouldaid in the recovery of the Xantus’ Murrelet and other crevice nestingspecies susceptible to rat predation.

B4: See Comment A14.

B5: The Park’s intent in distributing the DEIS through its website was toallow for wider distribution to the public. Distribution of the DEIS by CD-ROM is a less expensive way to disseminate the analysis. However, thePark distributed traditional “hard” copies to people who requested them, orto people who did not have computer access. The Final EIS will bedistributed in the same manner, however, the Park will review its websitedissemination procedure.

The Park attempted to make the document as readable and understandableas possible. Some of the technical language that is in the document is aproduct of the complex subject manner. Since most of the environmentalimpacts revolve around rodenticide toxicology, standard methods wereused for displaying and discussing this subject. Where possible theanalysis attempted to summarize this information.

B6: The environmental analysis that has been prepared for this projectmeets a very high standard of environmental analysis. Both the legalrequirement and the spirit of NEPA have been fulfilled. A supplementalEIS is necessary when substantial new information is discovered orsubstantial changes with environmental ramifications are made to theproposed action or an alternative to the proposed action. Becausesubstantial changes are not being made, a supplemental EIS is notnecessary. The Final EIS adds an option for preparing a supplemental EISshould first year implementation monitoring results indicate that objectivesare not being met, or environmental effects are different that what isdescribed in the FEIS (see pg 16 “Effectiveness and ValidationMonitoring”).

LETTER B: ENDANGERED SPECIES RECOVERY COUNCIL CONT.

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C1: A feasibility study was conducted in 1996 and a report submitted to theChannel Islands National Park (see Tershy et al. 1997). The probability ofcomplete removal, or eradication, of rats from Anacapa Island is high.Eradication of rats from islands has taken place on islands in the sub-Antarctic,to tropical atolls to the temperate Northern Pacific in Canada. The basicunderlying principal that resulted in the successful eradication programs hasbeen the delivery of a bait containing a rodenticide into every rat territory onthe island. This principal has been applied on all islands in all types ofclimates and sizes from small offshore rocks to the largest island of over 3000hectares (7,500 acres). The objective of the AIRP is eradication and notcontrol, therefore, treatment of the entire island is necessary for meeting thepurpose and need. The topography of Anacapa was taken into account whendeveloping the alternatives. Aerial broadcast is the only method for ensuringbait is delivered into every territory.

Appendix C is a list of successful eradications.

LETTER C: OJAI RAPTOR CENTER

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C2: Rat baits are formulated to be highly palatable to the target species. A battery oftests are required by the EPA to ensure that rats will consume the bait and will have thedesired effect on the target population. On Anacapa Island, we are delivering the baitto the rats at a time of year when the population is food stressed and are activelyseeking out high quality food resources such as that found in the bait. The bait isformulated to be highly palatable and attractive to the rat population. Islanderadications are most likely to be successful if they take place during the annualpopulation cycle when no reproduction is taking place and when rat numbers aredeclining. This insures that new-born rats will not emerge from their dens after all baithas been consumed, and that most rats will be food stressed and therefore more likelyto consume bait.

C3: Work conducted by Erickson (1990) documented the seasonal reproductivecondition of rats on Anacapa Island. His work has been cited throughout the EIS.

C4: The basic premise for all successful rat eradications is the delivery of bait into allrat territories. Territory is used synonymously with range.

C5: The application period corresponds to the late dry season on Anacapa Island.Bait will not be applied during the rainy season. During the dry season salamanderswould be deep within thick vegetation or deep cracks within the soil to avoiddessication.

C6: Alligator Lizards and Side-blotched Lizards are active year round on AnacapaIsland. The herpetofauna will be monitored before, during and after the eradication formeasuring impacts from the baiting and the predator release once rats are eradicated.See comments from A6.

C7: Secondary poisoning of birds of prey is of concern. Mortality of individual non-target birds will be mitigated where possible. However, from an ecological perspectivesuch mortality is only significant if it causes a long term population decline. There areno endemic birds of prey on Anacapa Island. The birds of prey on the Channel Islandsare habitat limited, i.e., there are more birds than there is available habitat. Data from araptor control effort around a colony of endangered Least Terns indicates thatpopulation effects of such removal are temporary.

LETTER C: OJAI RAPTOR CENTER CONT .

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LETTER D: U.S. ENVIRONMENTAL PROTECTION AGENCY

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D1: The Final EIS adds a monitoring element to all action alternatives. Insummary, should first year implementation monitoring results indicate that objectivesare not being met, or environmental effects are different from that what is describedin the FEIS (see pg 16 “Effectiveness and Validation Monitoring”) then asupplemental EIS would be prepared. The supplemental EIS would address potentialmodification of the project and their environmental effects.

D2: A Bait Spill Contingency Plan will be developed in case of an accidentalrelease of bait into both the terrestrial or marine environment. The handling andstorage of the bait, as well as the dispensing of bait (aerial or hand placement) willfollow California Code of Regulations (Title 3. Food and Agriculture) Division 6.Pesticides and Pest Control Operations managed by the California EnvironmentalProtection Agency, Department of Pesticide Regulation. These regulations outlinethe requirements of applicators and pesticide handling procedures. All of theseregulations will be complied with to ensure that there is a low risk of bait spill intosensitive environments. In addition, consultation with the US Coast Guard and NPSIPM staff will take place to develop a plan to respond to any bait spills. Includedwill be an outline of procedures for clean up, monitoring, and reporting of any baitspill incidents. All staff will be trained to standards and thoroughly understand theirresponsibilities in an emergency.

D3: The re-treatment of the 20 ha headland on Middle Island may becomenecessary for protection of East Island from re-invasion of rats. The intention oftreating the 20 ha headland is to open up territory for rats moving East on MiddleIsland, thus, as they move out of rat occupied territory into unoccupied territory, theywould utilize open territory on Middle Island. The size of the headland is equivalentto about 20-40 average sized adult rat territories. Thus, the highest probability of re-invading East Island would be late in the rat breeding season as juveniles aredispersing and are seeking their own ranges to occupy. Thus, the re-treatment periodwould only be necessary if rats are utilizing the headland extensively. Monitoringfor rat presence/absence will take place on the headland near the accessible pointsalong the shoreline. The results of the monitoring will evaluate location of detection,number of detections and rate of re-occupancy of the headland to evaluate risk of re-invading East Island. If the risk of re-invasion is deemed high, the 20 ha headland onMiddle Island will be re-treated. Similarly, monitoring stations will be placed on theEast Island near the accessible shoreline to evaluate presence/absence of ratssuggestive of re-invasion from Middle Island. Monitoring stations near theaccessible shoreline may include the use of non-toxic indicator blocks and the use ofbait containing the rodenticide brodifacoum. Thus, rats will likely have consumed alethal dose after they have been detected, presenting a lower risk of re-invasion.However, bait stations alone would not adequately defend against re-invasion of EastIsland because, the cliffs are extremely steep and unstable and bait stations could notbe placed on them. (Continued on next page)

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D3 Response Continued

D4: Appendix C is a list of successful island rat eradications. Once the timeand resources have been invested into an island eradication, it becomesnecessary to sustain those resources until the eradication is complete. Theeconomic resources have been devoted to this project and Anacapa Island fallswithin the size class of all successful island eradications. The project also has a2-3 year follow up monitoring plan for detecting the presence/absence of ratson the island post eradication. If rats are detected after eradication, thedetection response plan would be implemented as outlined in Appendix A.

D5: The rats on Anacapa Island have been a focus of a few studies (ICEG2000, Howald 1997, Erickson 1990 and Collins 1979). The rats are distributedunevenly across the island. The highest density of rats can be found along theshoreline, where the intertidal zone is likely and important foraging areaespecially during the lean dry season, and the cliffsides provide goodburrowing habitat. Rats utilize the rocky crevices of Anacapa Island and arefound to overlap quite extensively with the high quality murrelet nestinghabitat (McChesney et al. 2000). Erickson (1990) documented important rathabitats as those that provide adequate cover, either from dense brush or rockcrevices. Dense brush on the islands include coreopsis, sagebrush, and wildcucumber. The wooded canyons also provide excellent rat habitat. Grasslandhabitats found on Middle and East Island do not provide good habitat for ratsand thus, rats are found in low density. The presence of rocky crevicesproviding protection appears to be the most important feature for thedistribution of rats on Anacapa Island (Erickson 1990). Rats can be foundutilizing gullies and drainages on the islands as travel corridors, allowingfreedom of movement between feeding and burrowing areas. Radio-telemetrystudies conducted in 2000 and 1996 confirmed that movement of rats onAnacapa is primarily limited to drainages and gullies, and areas of denseshrubbery , very little movement of rats has been found on the grassland. InMay 2000, studies were initiated to evaluate if rats would cross the channelbetween East and Middle Island. Rats from Middle and East Island were livetrapped, fitted with a radio collar, and released in the channel, on the oppositeisland from which they were captured. After 3 months, no rat has beendetected to cross the channel. Re-invasion prevention is outlined in responseD3.

LETTER D: U.S. ENVIRONMENTAL PROTECTION AGENCY CONT.

D3 Thus, only a few bait stations could be placed along the accessible areas along theshoreline, thus, leaving the potential for rats not encountering the stations before theycross the channel.

If the risk of re-invasion is deemed high, then the headland on Middle Island would bere-treated outside of the September-December window. However, the impacts to non-target species would not be significant because treatment would be on a limited sectionof the island (20 ha), the sowing rate would likely be lower because of fewer rats,reducing the relative risks further, and Brown Pelicans do not nest on Middle Island.Although there would likely be non-target mortality from re-treating the 20 ha headlandof Middle Island, the impacts would not be significant.

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LETTER F: CALIFORNIA COASTAL COMMISSION.

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F1: On September 7, the Park sent a “Negative Determination” to the CaliforniaCoastal Commission. In the letter the Park provided documentation as to why a“Negative Determination” was appropriate for this project.

G1: The NPS is aware of the MBTA and is mitigating to minimize any potentialimpact to non-target birds that would fall under the MBTA. This project is asignificant conservation action to benefit many bird species in the long term. Uponthe successful removal of rats from the island, there will be a rebound of seabirdsand landbirds that are currently impacted by rats. In the long term, the restorationof bird habitat on Anacapa Island will enhance the local bird population protectedunder the MBTA.

LETTER G: U.S. FISH AND WILDLIFE SERVICE

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G2: The risk of secondary poisoning of scavengers is already partiallymitigated by the fact that most rats and mice (87-100%) will die belowground after exposure to the rodenticide. However, NPS will further mitigateagainst secondary poisoning through removal of any carcasses found aboveground. Regularly scheduled “sweeps” of the island will be conducted bypersonnel seeking and retrieving any carcass found after rodenticideapplication. Sweeps will be conducted until no carcasses are found for 5days.

G3: The endangered Island Malacothrix (Malacothrix squalida) is foundon Middle Anacapa Island. To mitigate against any damage to this species,the NPS botanists will identify and mark known locations of this endangeredplant. Personnel working on Middle Anacapa Island will be advised of thepresence of the plant and will be briefed thoroughly on techniques tominimize disturbance/trampling of the area surrounding malacothrixlocations.

G4: The Park has been concerned about the squid fishery around Parkislands. We have submitted suggestions to the California Department of Fish& Game for measures that would mitigate impacts to seabirds.

LETTER G: U.S. FISH AND WILDLIFE SERVICE CONT.

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LETTER H: PACIFIC SEABIRD GROUP

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LETTER H: PACIFIC SEABIRD GROUP CONT.

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H1: Chapter 3 page 40 will be changed to read as follows:

“The executive committee of the PacificSeabird Group has authorized a committee todraft a petition to list the Xantus Murrelet forprotection under the Endangered Species Act.”The Pacific Seabird Group, however, has yet torender an opinion on the merits or reasons forlisting Xantus’ Murrelet.”

H2: The most current information of seabird predation, including Xantus’Murrelet predation, by rats is from surveys conducted in 1997 (summarized inMcChesney et. al. 2000) , 2000 (H.Carter unpublished data), and 2000 (P. Martinpers. comm).

Since publishing of the DEIS, the cited “H.Carter Unpublished Data pg 33 DEIS”is now a published report (see citation McChesney et al. 2000). Results of thesurvey show that they found evidence of nesting murrelets at only two sites in areasthat were fully accessible to rats, or 0.4% of 505 potential sites investigated onground surveys. Both eggshells showed evidence of rodent predation and were inareas where rats appeared to be common. In contrast, at Santa Barbara Island(where rats do not occur), similar surveys in 1991 found murrelet eggshellfragments in 29.4% of potential sites, including 27.9% of crevice and 39.6% ofshrub sites.

H.Carter (unpublished data), researchers collecting baseline Xantus’ Murreletpopulation data noted the following during sea cave nest surveys: Eleven nestswere found in sea caves with known nesting in the past at Anacapa Island. Somecaves with previous nesting were empty. No murrelets were handled and nonewere flushed from nests during surveys. About 4-5 eggs appeared to have beendepredated by rats.

P.Martin (Unpublished data), monitoring gull productivity grids in June 2000found evidence of rat chewed carcasses on 10 gull chicks. Evidence stronglysuggests rat predation because of the condition of the carcass (brain cavity openedand eaten), and location of where the carcasses were found (thick brush withnumerous rat burrows). It is not known if the gulls were previously dead, or if ratspreyed upon the chicks.

Evidence of rat impacts to the Xantus’ Murrelet including: low nesting numbers insuitable habitat as compared to Santa Barbara Island; low population numbers incomparison to Santa Barbara Island; evidence of rat predation on murrelet eggs;and extremely low nesting success in areas known to be accessible to rats whenconsidered together suggests that rats are suppressing Xantus’ Murrelet populationnumbers on Anacapa Island, an area that has similar nesting habitat availability asrat free Santa Barbara Island.


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H3: No pre-rat historical breeding population data is known to exist for theXantus’ Murrelet or other seabirds for Anacapa Island. Because no pre-ratpopulation data is available the Park has to rely on: 1) population datacomparisons between Anacapa and Santa Barbara Island; 2) known rat impacts toseabird colonies on other islands; and 3) direct evidence of rat predation onAnacapa Island seabirds to make an assessment on the impact rats are having onAnacapa Island seabird colonies. The Park’s assessment is that rat impacts aresuppressing the crevice nesting seabird population on Anacapa Island. Thisassessment is consistent with the suggestions given by species experts thateradicating rats to protect crevice-nesting seabirds is a necessary conservationproject.

H4: The most complete assessment of potential nesting habitat for crevice-nestingseabirds on Anacapa Island was done by McChesney et. al (2000). The executivesummary of this report can be found in Appendix D.

H5: See H2.

H6: The treatment of the islets would be carried out over a two year period. EastIsland would be treated in Year 1. In Year 2, Middle and West Island would betreated. In between treatment of East and Middle/West Islands, mice could bemoved from Middle and West Island to rat-free East Island. The mousepopulation would be allowed to grow, and individuals would be transported over toMiddle and West Island post eradication thereby ensuring the viability and geneticdiversity of the mouse population. This mitigation measure may be implementedindependently or in conjunction with other mitigation measures outlined in Chapter2.

H7: Both mice and rats are rodents, and the bait will be attractive to both species.It is a logistical challenge to eradicate rats without having a significant impact onthe local Deer Mouse population. The NPS recognizes the need for theconservation of the Anacapa Deer Mouse and is a priority of the AIRP. The NPSwill ensure the genetic diversity and viability of the Deer Mouse population isprotected (See H8 –H10).

H8: The conservation and management of Anacapa Island deer mice is a highpriority for the AIRP. The genetic and morphological status of the Anacapa DeerMouse has been investigated using genetics, morphometrics and computermodeling (mitochondrial DNA (mtDNA) analysis, morphometric discriminantfunction analysis and population viability analysis (see Pergams et al. 2000)). Themorphological and genetic analysis confirms that the Anacapa Deer Mouse is adistinct subspecies when compared to other populations from the mainland andother islands. The mice on each islet are not genetically distinct from the otherislets indicating that the population could be managed as one unit. In other words,the mice across all three islets are genetically indistinct. The results of thecomputer modeling have indicated that 1000 mice collected across all three isletswould be adequate to ensure a viable and genetically diverse population.


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H9/H10: Peromyscus spp. are one of the most ubiquitous small mammals inNorth America. These populations are highly tolerant to disturbance andhabitat alteration and populations are very resilient. They readily breed and dowell in captivity. Populations of Peromyscus are managed in laboratories suchas at the Brookfield Zoo in Brookfield, Illinois, or the Peromyscus GeneticStock Center at the University of South Carolina. The capture, handling andbreeding methodology has been well documented in the scientific literature.Consultation with Peromyscus and genetic experts from the Brookfield Zooand University of Illinois is underway to develop a protection plan that willincorporate handling/breeding methodology to ensure genetic diversity and aviable population. The plan will include a re-release schedule includingmonitoring ensuring that the population will remain viable post eradication.The Effectiveness and Validation Monitoring program will aid in thedevelopment of an effective management program for the Anacapa DeerMouse by identifying problem areas that would allow changes to the protectionplan prior to completion of the baiting.

Changes to the Deer Mouse protection plan have been incorporated intoChapter II, page 17.

H11: The Non-Native Rodent Introduction Prevention Plan has beenadequately outlined on page 14. The basic premise is that through activerodent control around all departure points, as well as a strong educationalcomponent, there would be a low probability of re-introducing rats on to theisland.

H12: The numbers and species of raptors likely affected by the program havebeen discussed in Chapter IV, page 73. Secondary poisoning of birds of preyis of concern to the AIRP. Mortality of individual non-target birds will bemitigated where possible. However, from an ecological perspective suchmortality is only significant if it causes a long term population decline. Thereare no endemic birds of prey on Anacapa Island. The birds of prey on theChannel Islands are habitat limited, i.e., there are more birds than there isavailable habitat. Most of the birds of prey, as well as ravens, are killed in thevicinity of Least Tern breeding colonies in an ongoing effort to protect thisendangered species from predation. The ongoing nature of predatory birdcontrol around Least Tern colonies suggests that any decrease in predatorybirds due to the rat removal on Anacapa will be temporary.

Consultation with the Predatory Bird Research Group (PBRG), University ofCalifornia, Santa Cruz, is underway to develop mitigation plans for birds ofprey. The Effectiveness and Validation Monitoring program will aid in thedevelopment of an effective raptor mitigation program which may include anyor all aspects of the mitigation as outlined on page 73.


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FINAL ENV IRON MEN TAL IMPACT ST AT E MEN T

REFERENCES - 119

Index

air quality, 36American Trader, 86, 84, 87Anacapa, iv, 3, 4, 5, 6, 7, 13, 11, 13, 14, 15, 16,

17, 18, 19, 20, 21, 22, 23, 24, 26, 27, 28, 29,33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44,45, 46, 48, 51, 52, 53, 54, 55, 56, 57, 58, 59,60, 61, 62, 65, 67, 68, 69, 70, 72, 73, 74, 75,76, 77, 78, 81, 82, 83, 85, 86, 87, 84, 85, 88,108, 109, 113, 114, 116, 117

anticoagulant, 21, 22, 23, 24, 27, 48, 49, 52, 59,63, 65, 66, 68, 70, 81, 85, 112, 113, 115

Ashy Storm Petrel, 16, 39

bait, 5, 6, 12, 13, 14, 18, 19, 20, 21, 22, 23, 24,25, 26, 27, 29, 48, 49, 50, 51, 52, 53, 54, 55,56, 57, 58, 59, 60, 61, 62, 63, 65, 66, 67, 68,69, 70, 71, 72, 73, 74, 75, 76, 77, 81, 83, 84,85, 117

bait shyness, 5, 27, 52biological control, 29black abalone, 45Black rat, 4Black Rat, 15, 18, 19brodifacoum, 21, 22, 24, 25, 27, 48, 49, 50, 51,

53, 62, 63, 64, 65, 66, 68, 70, 74, 76, 77, 79,81, 84, 111, 113, 116, 117

bromethalin, 27Brown Pelican, 9, 14, 40, 41

California Sea Lion, 9, 31, 42, 43cliffsides, 5, 20, 21, 22, 23, 24, 25, 26, 29, 51,

54, 66, 67, 83Climate, 9, 31, 35Council on Environmental Quality, 15cumulative impacts, 48, 78

deer mouse, 6, 15, 17, 42, 53, 56, 58, 77, 78diphacinone, 24, 25, 27, 48, 49, 50, 63, 64, 66,

74, 75, 76, 81Double-crested Cormorant, 39Drought, 36

East Island, 21, 15, 18, 19, 20, 22, 23, 25, 26, 27,51, 56, 76, 83, 84

ecosystem, 5, 18, 11, 20, 22, 25, 29, 48, 53, 59,60, 61, 68, 69, 77, 86, 87, 117

Endangered Species Act, 15, 26, 40, 54endemic, 6, 17, 18, 15, 17, 37, 38, 41, 54, 78,

117Environmental Consequences, 5, 88EPA, 21, 18, 27, 62, 68, 74, 77, 111

Frenchy’s Cove, 15, 46, 83

Geology, 9, 31, 33, 34, 113granivores, 41

Harbor seals, 13, 44Herpetofauna, 8, 9, 11, 10, 14, 31, 37, 55, 57, 70

invertebrates, 18, 19, 13, 14, 37, 41, 45, 53, 54,61, 62, 64, 68, 72, 75, 78, 86, 87

Invertebrates, 8, 9, 10, 13, 31, 36, 37, 45, 47, 55,57, 68

Island Conservation and Ecology Group, 4, 11,84, 86, 113, 114, 117, 118

landbird, 6, 38, 73, 74, 75

marine mammal, 6, 108, 109Middle Islet, 19, 22, 25, 34Miocene, 33, 34Mitigation, 6, 76, 78, 84, 86

NEPA, 4, 11, 19, 84Non-Target Impacts, 5, 10, 12, 53Non-target species, 4, 53, 59

Pacific Seabird Group, 87, 115Pacific Slender Salamander, 37Peromyscus maniculatus anacapae, 15, 41. See

Anacapa Deer Mousepinnipeds, 17, 43, 44, 66, 67, 108primary exposure, 6, 13, 15, 20, 23, 51, 53, 59,

60, 61, 62, 66, 67, 68, 69, 70, 71, 72, 74, 76,83

Prince, 4, 18proposed action, 4, 5, 11, 12, 13, 14, 15, 32, 59,

82, 85, 88public meetings, 4

Rat Detection Response Plan, 18, 20, 21, 23, 24,26

Rattus rattus, 15, 19, 40, 49, 50, 111, 113, 117,118. See Black rat

Resources Management Plan, 16RMP, 16rodenticide, 5, 6, 11, 12, 13, 14, 15, 19, 21, 24,

27, 29, 48, 49, 50, 51, 52, 53, 54, 58, 59, 60,61, 62, 63, 65, 66, 68, 69, 70, 71, 72, 74, 75,77, 78, 81, 82, 83, 85, 86

Rodenticide, 6, 10, 13, 14, 48, 53, 67, 110, 111,116

San Clemente, 43


FINAL ENV IRON MEN TAL IMPACT ST AT E MEN T

REFERENCES - 120

San Miguel, 15, 22San Miguel Island, 22, 43San Nicolas, 43, 109Santa Barbara, 4, 12, 18, 32, 33, 36, 37, 40, 41,

42, 43, 53, 82, 85, 86, 87, 108, 109, 110, 112,113, 115, 117

scoping, 84seabird, 6, 39, 65, 72, 81, 82, 86, 84, 109, 113secondary exposure, 6, 13, 14, 24, 59, 60, 61, 62,

63, 64, 65, 66, 72, 74, 75, 76, 77, 78Side-blotched Lizard, 37Soils, 9, 31, 34Southern Alligator Lizard, 37Sutil, 4, 18

Target species, 4the American Traders Trustee Council, 84The National Historic Preservation Act;, 15

U.S. Fish and Wildlife Service, 39, 40, 86, 118

vertebrate, 4, 16, 41, 60, 79, 81, 85visitation, 4, 6, 10, 15, 18, 31, 43Visitation, 4, 6, 8, 11, 10, 12, 15, 18, 82, 85Vitamin K1, 27, 84

Warfarin, 5, 19, 27, 52, 84

Xantus’ Murrelet, 16, 19, 39, 41, 110, 115, 117

zinc phosphide, 27

Appendix A - 121

Appendix AThis appendix is divided into two sections: the Shipwreck Response Plan and the Rat Detection

Response Plan. Each of the response plans are in flowchart form, designed for ease of reading andrequired steps to implement an eradication. The objective of this document is to provide a pathway formanagers and personnel to successfully implement the eradication of introduced rodents. This flowchart is designed to serve as a guide for immediate action. However, the recommended actions should befollowed up as soon as possible by a meeting of the AIRP working group to examine the availableinformation and design the best possible plan. The Shipwreck Response Plan is designed to directactions of managers and personnel toward implementing the Rat Detection Response Plan. Once rats areconfirmed on the islands, the Rat Detection Response Plan directs personnel and managers toward aresolution, i.e., eradication of the introduced rodent. If rats would be introduced via transport ofequipment or goods, the Rat Detection Response Plan would be implemented, bypassing the ShipwreckResponse Plan.

The plans follow on the next pages.


.........


Appendix A - 122

AIRP: Shipwreck Response PlanObjective: The objective of this plan is to provide a pathway for managers and personnel to respond to shipwrecksthat potentially could introduce non-native rodents to Anacapa Island.

Instructions: Follow the flowchart to implement an appropriate action. A description for each box is attached. Beclear about each step before moving on.

Shipwreck is confirmed or imminent

Island Ranger or observer calls in shipwreck to dispatch or after hours emergency contact

Dispatch or emergency contact alerts resource manager.

Resource Manager activates Non-native Rodent Response Team which travels to site.

WestAnacapa,SantaBarbara, orPrince Island

East or Middle Island

Contact USFWS andSeabird Biologist atNPS

Yes

No

Shipwreck Inspection

Which island is thewreck?

Are pelicans expected to nest withinthe month or are nesting??


Appendix A - 123

No

Shipwreck Inspection:

Rodent sign found, or you couldn’t get on board because of safety?

Rat orunsure

What type of rodent sign did you find?

Monitor for rat sign on shoreYes

MouseMonitor for mouse sign on shore

Implement Rat Detection Response Plan


Appendix A - 124

AIRP: Response Plan for Positive Detection of Rats PostEradication

Potential Situation: Rats have been detected due to incidental introduction or shipwreck. Tools and budgetsnecessary are available.

Instructions: Follow the flowchart to implement an appropriate action. Be clear about each step before moving on.

How sure are you that rats are present?

Positive Immediately report incident toResource Manager and beginsearching for rat sign

Immediately report incident to Resource Manager. Describe incidentand advise implementing response plan

Where were ratsfound?

East or Middle Island

Are pelicans nesting or are they expected tonest within the month??

Contact USFWS andSeabird Biologist atNPS

Yes

No

Problem Evaluation

Maybe

WestAnacapa,SantaBarbara, orPrince Island


Appendix A - 125

Hand Broadcast only if rain is notexpected for at least 7days. Bait Stations

Problem Evaluation:

What is the Extent of the Problem?

Restricted RatNumbers: Local

Distribution.HotspottingPossible?

Widespread Distribution of Ratsor Hotspotting not possible b/cof inaccessibility

Yes

No

What is the location of detection?

Cliff and/or Shoreline

Top

Evaluate Risk to Non-Targets

Acceptable Risks

Notify: Res. Mgr., Seabird Bio.

Problem Resolution

Unacceptable Risks

Mitigate or Wait untilRisk Period Passes

Non-Target Evaluation:Gulls on Top of Island?

No Yes

Were Rats Detected inProximity to Landing Cove,Buildings, Campground or

areas where the GeneralPublic Frequent?

No Yes

Go to Widespread Rat ProblemResolution Section


Appendix A - 126

Widespread Rat Problem Resolution:Hotspotting not possible due to inaccessibility or a large problem?

What is the location of detection?

Cliff and/or Shoreline

Top

Acceptable Risks

Notify: NPSIPM, Res.Mgr, Sea-Bird Bio

Unacceptable Risks

Mitigate or Wait until RiskPeriod Passes

Non-Target Evaluation:Gulls on Top of Island?

No Yes

Were Rats Detected in Proximityto Landing Cove, Buildings,

Campground or areas where theGeneral Public Frequent?

No Yes

Has mouse population recovered or stillmaintaining a captive population – otherislands or in lab?

Yes No

Consult with Mouse Specialists before movingahead – advise of treatment plan.

Notify appropriate agencies and ensurepermission has been granted beforemoving forward!!

Aerial broadcast as per AIRP StandardOperating Procedure

Consider using bait stations whereverpossible. If necessary, do a combinationof bait stations and aerial broadcast.

Evaluate Risk to Non-Targets

Problem Resolution

Appendix B - 127

Appendix B

The Birds of Channel Islands National Park(adapted from: Jones et al. 1985)

Symbols:

Abundance: a – abundant; c – common; u – uncommon; o – occasional; r – rare; x – accidental

Seasonal Occurrence: FR – former resident; FT – fall transient; FV – former visitor; IR – introduced resident; R –resident; SR – summer resident; ST – spring transient; SV – summer visitor; V – visitor;WV – winter visitor

• - breeds on islands noted.

SanMiguelIsland

SantaRosaIsland

SantaCruz

Island

AnacapaIsland

SantaBarbaraIsland

LOONSRed – throatedLoon

oWV uWV uWV oWV oWV

Pacific Loon cWV aWV cWV uWV cWVoSV oSV

Common Loon cWV cWV uWV oWV oWVoSV

GREBESHorned Grebe uWV cWV uWVEared Grebe aWV aWV aWV aWV aWV

oSV oSV

Western Grebe uWV cWV cWV oWV oWVALBATROSSES

Black – footed Albatross rV rVSHEARWATERS

Northern Fulmar oWV uWV uWV oWV oWVPink – footed Shearwater oSV oSV oSV oSV oSVSooty Shearwater uSV uSV uSV uSV uSVBlack-vented Shearwater rWV rFT rFT

STORM-PETRELSLeach’s Storm-Petrel*

uSR

Ashy Storm-Petrel* cSR uSR cSRBlack Storm-Petrel* cSR


.........


Appendix B - 128

TROPICBIRDSRed-billedTropicbird

rSV xFT xST xFT

PELICANSBrown Pelican aV aV rR* aR* aR*

CORMORANTSDouble –crestedCormorant

Cormorant

cR* cV cR* cR* cR*

Brandt’sCormorant*

aR aR aR aR aR

Pelagic Cormorant* cR cR cR cR uRFRIGATEBIRDS

Magnificent Frigatedbird xST rSV xSVHERONS, EGRETS, BITTERNS

Great Blue Heron oV uV uV oV oVCattle Egret xWV oWV oWV oWV rWVGreen-backedHeron

oST xFT

oFTBlack-crowned Night-Heron xWV rST xST

GEESE, DUCKSGreater White-fronted Goose oFT FVSnow Goose xWV oWV oWV xFTBrant rWV oWV oWV xST oSTCanada Goose xWV oWV oWV rWVWood Duck rFTGreen-winged Teal cWV oWV xWV

Mallard oWV oWVxSV

Northern Pintail xSV cWV oWV xFTrFT

Blue-winged Teal oFt oFToST oST

Cinnamon Teal xFT uWV uWV xFTAmerican Wigeon cWV xFTSurf Scoter aWV aWV aWV aWV cWV

oSV oSV oSVWhite-wingedScoter

cWV cWV cWV oWV rST

oSVRed-breasted Merganser uWV uWV uWV oWV xSTRuddy Duck rFT oWV xSV

OSPREY, HAWKS, EAGLESOsprey rFT oFT rFT rFT

xST rSTBald Eagle FR FR FR FR FR

oWV xVNorthern Harrier oWV oWV oWV oWV oWV

xSV xSV


Appendix B - 129

Sharp-shinnedHawk

oFT oWV uWV

Cooper’s Hawk oFT oWV uWV rFToST

Red-tailed Hawk uR* uR* uR* uR* xSVuWV

Golden Eagle xV rV oWVFALCONS

American Kestrel* uR cR cR uR uRMerlin rFT oWV oWV xST

rSTPeregrine Falcon FR FR FR FR FR

uIR* oV oV oWV oWVPHEASANTS, TURKEYS, QUAIL

Chukar* uIRCommon Peafowl* uIRWild Turkey* uIRCalifornia Quail* cIR cIR

RAILS, COOTSVirgina Rail rWV xFTSora xFT oST xST xSVAmerican Coot xWV uWV uWV rFT

xSV+PLOVERS

Black-bellied Plover aWV aWV cWV rWV uWVuSV uSV uSV

Lesser Golden-Plover

oV xFT xWV xST

Snowy Plover cR* cR* cR* xSTSemipalmatedPlover

oWV oFT oFT xFT

oST oSTKilldeer oFT cR* cR* oFT rST

rSTMountian Plover FV oWV

OYSTERCATCHERSAmerican Oystercatcher rR* xR+ xSVBlackOystercatcher*

cR cR cR cR cR

SANDPIPERS, PHALAROPESGreater Yellowlegs oFT oFT oFT xFT

oST oST oSTSolitary Sandpiper xFT xFT oFT xFTWillet cWV aWV cWV uWV uWV

uSV uSV uSV oSVWandering Tattler cWV cWV cWV cWV cWV

uSV oSV oSV uSV uSVSpotted Sandpiper oWV oWV uWV uWV oST

oFTWhimbrel cWV cWV cWV oWV cWV

uSV uSV uSV uSV


Appendix B - 130

Long-billed Curlew oV uWV oFT uSVoST

Marbled Godwit uWV cWV uWV rSToSV uSV oSV

Ruddy Turnstone cWV cWV uWV oST oFToSV oSV oST

Black Turnstone aWV aWV cWV cWV uWVuSV oSV uSV oSV

Surfbird rST oFT xST rFT xSTrST

Sanderling cWV aWV aWV xFT rFToSV oSV

Western Sandpiper oFT uWV oFT oFT xSToST oST

Least Sandpiper uWV cWV oWV xFT rFTrST

Baird’s Sandpiper rFT xFTPectoral Sandpiper rFT oFT xFT xFTDunlin oFT uWV oWV xSTShort-billedDowitcher

rFT xSV xFT xFT xST

rSTLong-billedDowitcher

xFT oWV xFT

Common Snipe rFT uWV xFT rFTrST

Red-necked Phalarope oST oST oSToFT oFT

Red Phalarope oST oST oStoFT oFT

JAEGERS, GULLS, TERNSParasitic Jaeger xWV oV oVFranklin’s Gull xST rFT xST

rSTBonaparte’s Gull oWV uWV uWV oWV oWVHeermann’s Gull cWV aWV aWV cWV uWV

oSV oSV oSV oSV oSVMew Gull uWV uWV cWV uWVCalifornia Gull cWV cWV cWV uWV uWVHerring Gull uWV uWV uWV xST oWVWestern Gull* aR aR aR aR aRGlaucous-wingedGull

cWV oWV oWV oWV oWV

Black-legged Kittiwake uWV uWV uWV uWV uWVRoyal Tern cWV cWV cWV oWV oWVForster’s Tern xFT oFT xST

AUKS, MURRES, PUFFINSCommon Murre oWV uWV uWV uWV xST

FRPigeon Guillemot* cSR cSR cSR uSR cSRXantus’ Murrelet* uSR uSR uSR aSR


Appendix B - 131

Cassin’s Auklet aR* oV uR* oV uR*Rhinoceros Auklet oWV oWV oWV oWV oWVTufted Puffin FR rV FR FR FR

xSVPIGEONS, DOVES

Rock Dove oV oV oV oV oVBand-tailed Pigeon oST oST uWV oSV

xSVWhite-winged Dove xFT rFT rFT rFT

xWV rSTMourning Dove cSV cR* cR* cSV cSV+

rWV rWVBARN-OWLS

Common Barn-Owl*

uR uR uR uR uR

TYPICAL OWLSBurrowing Owl uWV uWV uWV uWV uR*Long-eared Owl oWV xST oVShort-eared Owl rWV uWV uR*Northern Saw-whet Owl uR*

GOATSUCKERSLesser Nighthawk rSt oFT uST

rFTCommon Poorwill uWV rST xFT

SWIFTSChimney Swift rSTVaux’s Swift xST oFT uFT uFT oFT

oST oST oST oSTWhite-throatedSwift

rST uR* cR* uSR* oSV

HUMMINGBIRDSAnna’sHummingbird

cSR* oST uR* rST oST

xFT oFT oFTCosta’sHummingbird

rST oST rST oST

rSV rFT rSV rFTRufousHummingbird

xST xFT xWV uST

xST xST xFTAllen’sHummungbid

cR* cR* cR* cR* oFT

oSTKINGFISHERS

Belted Kingfisher oWV oV uWV uWV uWVxSV

WOODPECKERSLewis’ Woodpecker rWV uWV xFT xFTAcorn Woodpecker xST rWV cR* rWV xFTYellow-bellied Sapsucker oWVRed-breasted Sapsucker rWV uWV uWV xFTNorthern Flicker uWV uWV cR* uWV uWV


Appendix B - 132

xSVTYRANT FLYCATCHERS

Olive-sidedFlycatcher

oST oFT xST uST

oST oFTWestern Wood-Pewee uST uST cST uST cST

uFT cFT uFT uFTWillow Flycatcher oFT oST uST

oFT uFTHammond’s Flycatcher rST xST rST oSTDusky Flycatcher oSTGray Flycatcher rST oSTWestern Flycatcher cST cSR* uSR* rSR* cST

cFT cFTBlack Phoebe uR+ cR* uSR* uWV uWVSay’s Phoebe cWV vWV cWV cWV cWV

xSVAsh-throated Flycatcher oST uSR* uST cST

oFT cFT cFTCassin’s Kingbird xST rV xFT oFT rST

oFTWestern Kingbird oST oST uST oST uST

xFT uFT oFT uFTScissor-tailed Flycatcher xST rST xST

LARKSHorned Lark aR* aR* aR* oWV aR*

FRSWALLOWS

Purple Martin xFT rSTTree Swallow xST oST xFT oST

xFTViolet-greenSwallow

xSV xFT xST xST oST

xSV xSV xFTNorthern Rough-wingedSwallow

xST xST oST

xFT oFTCliff Swallow xST xST oST oST oSV

xFT xFT rFT oFTBarn Swallow* cSR cSR cSR cSR uSR

JAYS, CROWSScrub Jay* cRClark’s Nutcracker rWVCommon Raven FR aR* aR* uR FR

oV xSTBUSHTITS

Bushtit cR* xSVNUTHATCHES

Red-breasted Nuthatch uWV uWV uR* xFT oSToFT

White-breasted Nuthatch rWV


Appendix B - 133

CREEPERSBrown Creeper rWV oWV

WRENSRock Wren* cR cR uR uR uRCanyon Wren rRHermit Warbler oST oST oST cST cST

xFT uFT uFT oFT oFTxWV

Palm Warbler rFT xFT oFT xSTxST oFT

Blackpoll Warbler xST oFT xFT rSTrFT oFT

Black-and-white Warbler xFT xST xST oSTxWV rFT

American Redstart xST oFT oFT xST rSTxFT oFT oFT

Ovenbird oSToFT

NorthernWaterthrush

xFT rFT xST rST

MacGillivray’sWarbler

xFT oFT oST oST uST

oFT oFT uFTCommonYellowthroat

uWV oFT uWV oFT oST

xWV xSV xST xSVoFT

Wilson’s Warbler uST uST uST uST uSTuFT uFT uFT cFT cFT

xWVYellow-breastedChat

xST xFT xFT xST oST

xFT xFTTANGERS

Summer Tanger xSV rSTWestern Tanger oST oST oST uST uST

oFT uFT uFT uFT cFTGROSBEAKS, BUNTINGS, SPARROWS

Rose-breasted Grosbeak xFT rST uSToFT

Black-headed Grosbeak uST oST cSR* uST cSToFT oFT xWV uFT uFT

Blue Grosbeak xST oFT rST oSTrFT rFT

Lazuli Bunting oST oST uST cST cSToFT uFT uFT uFT

Indigo Bunting xST rST uSToFT

Green-tailedTowhee

xST oFT oFT oST

xFT xWV oFT


Appendix B - 134

Rufous-sidedTowhee

oFT cR* cR* oWV uFT

xST rWVRufous-crowned Sparrow* cR uRChipping Sparrow uST cSR* cSR* cSR* uST

uFT xWV cFTClay-coloredSparrow

xFT xFT oFT

xSTBrewer’s Sparrow xST xST

rFT rFTVesper Sparrow oFT oFT oFT oST

uFToWV

Lark Sparrow uFT xST oST oSToWV cWV xSV oFT

uFTBlack-throated Sparrow xFT xST oST

oFT rFTLark Bunting rFTSavannah Sparrow cWV cWV cWV uST cWV

cFTGrasshopperSparrow

uSR* xST rST

Fox Sparrow oWV oWV cWV oST oWVoFT

Song Sparrow aR* aR* uR* xFT FRLincoln’s Sparrow oST oFT uWV oWV oWV

oFT xWVGolden-crowned Sparrow uWV cWV aWV cWV cWVWhite-crowned Sparrow cWV aWV aWV aWV aWVDark-eyed Junco oST cWV cWV oST uST

cFT cFTChestnucollared Longspur rFT

ORIOLES, BLACKBIRDSBobolink xST xFT oFT oST

rFT oFTRed-wingedBlackbird

oST uR* oFT oST

oFT oFTTricolored Blackbird xFT oST rSTWesternMeadowlark*

cR aR cR cR cR

Yellow-headed Blackbird rFT oST oST oST oSToFT oFT oFT oFT

Brewer’s Blackbird oST oST oST oST oSToFT oFT oFT

Brown-headed Cowbird oFT uWV uWV oST uSTxST uFT uFT

Hooded Oriole xST xFT oFT oSToFT


Appendix B - 135

Northern Oriole oST xST oST oST uSToFT oFT uFT uFT

FINCHESPurple Finch xST oWV uWV oSTHouse Finch aR* aR* cR* cR* FR

oVRed Crossbill oVPine Siskin xST uWV oST rWV

oFTLesser Goldfinch uSR* cR* cR* xST oST

uFT uFTLawrence’sGoldfinch

xST oST oST oST oST

oFT oFT oFT oFTxWV

American Goldfinch xWV oWV oWV rSTxSV

OLD WORLD SPARROWSHouse Sparrow xST xST xST oST

FR xFT

ACCIDENTAL SPECIES

Pied-billed Grebe (SMI, SRI) Least Flycatcher (SRI)Least Storm-Petrel (SMI) Eastern Flycatcher (SMI, SRI, SBI)Brown Booby (SMI) Bank Swallow (SMI, SBI)American White Pelican (AI) American Crow (SRI, AI)Great Egret (SRI) American Dipper (SCI)Snowy Egret (SRI, SCI, SBI) Gray Catbird (SCI)Northern Shoveler (SRI, SCI) Bendire's Thrasher (AI, SBI)Lesser Scaup (SRI, AI) Red-throated Pipit (SMI, SCI)Harlequin Duck (SMI) Gray Vireo (SBI)Black Scoter (SMI, SRI, SCI) Philadelphia Vireo (AI, SBI)Common Golden Eye (SRI, SCI) Red-eyed Vireo (SBI)Black-shouldered Kite (all islands) Lucy's Warbler (SCI)Swainson's Hawk (SCI) Northern Parula (SMI, SBI)Rough-legged Hawk (SCI, SBI) Cape May Warbler (SRI, SBI)Prairie Falcon (SRI, SCI, SBI) Black-throated Blue Warbler (SMI, SRI)Black-necked Stilt (SCI) Black-throated Green WarblerAmerican Avocet (SCI) (SMI, SCI, SBI)


Appendix B - 136

Lesser Yellowlegs (SCI) Blackburnian Warbler (SCI, SBI)Upland Sandpiper (SBI) Graces's Warbler (SCI)Red Knot (SMI, SRI) Bay-breasted Warbler (SRI, SBI)Wilson's Phalarope (SBI) Kentucky Warbler (SBI)Pomarine Jaeger (SRI, SCI, AI, SBI) Canada Warbler (SRI)Ring-billed Gull (SMI, SCI, SBI) Painted Redstart (SCI)Thayer's Gull (SMI, SCI, AI) Dickcissel (SBI)Glaucous Gull (SMI) Anerican Tree Sparrow (SCI)Caspian Tern (SRI) Black-chinned Sparrow (SCI, SBI, AI)Artic Tern (SRI, SCI) Sage Sparrow (SCI, SBI)Craveri's Murrlett (SBI) Swamp Sparrow (SCI)Horned Pufin (SMI, AI) White-throated Sparrow (SCI, AI, SBI)Spotted Dove (SBI) Harris' Sparrow (SBI)Ringed Turtle-Dove (SBI) McCown's Longspur (SBI)Flammulated Owl (SBI) Lapland Longspur (SRI, SBI)Great Horned Owl (SBI) Rusty Blackbird (SRI, SCI)Black Swift (SCI, AI) Scott's Oriole (SCI, AI)Calliope Hummingbird (SBI) ANACAPA ISLAND- AI SAN MIGUEL ISLAND- SMI

Nuttall's Woodpecker (SMI, SRI,SCI)

SANTA CRUZ ISLAND- SCI SANTA BARBARA ISLAND-SBI

Northern (Yellow-shafted) Flicker(AI, ABI)

SANTA ROSA ISLAND- SRI

Appendix C - 137

Appendix CIsland Rat Eradications Worldwide

Species Island SIZE (HA) Technique Reference

R. norvegicus Cox, Canada 10 Brodifacoum Kaiser et al. 1997R. norvegicus Otata, NZ 15 Brodifacoum & 1080 Veitch & Bell 1990R. exulans Korapuki, NZ 17 Brodifacoum Veitch & Bell 1990R. rattus Great Bird, Antigua 20 Brodifacoum K. Lindsay pers. comm.

R. rattus Tawhitinui, NZ 21 Brodifacoum Taylor 1993Rattus rattus Ille Aux Aigrettes,

Mauritius 25 Brodifacoum B. Simmons, pers. comm.

R. rattus Somes, NZ 32 Brodifacoum Veitch & Bell 1990R. norvegicus Titi, NZ 32 Brodifacoum Veitch & Bell 1990R. exulans Double, NZ 32 Brodifacoum Veitch & Bell 1990R. norvegicus Lucy, Canada 40 Brodifacoum Buck 1995Rattus exulansRattus rattus

12 Islets in the NewCaledonia Group 48.5 Brodifacoum B. Simmons, pers. comm.

R. norvegicus Rasa, Mexico 60 Brodifacoum J. Ramirez pers. comm.R. norvegicus Ailsa Craig, UK >60 Warfarin B. Zonfrillo, pers. comm

Rattus exulans Onoeo, Pitcairn Group,Pacific 62 Brodifacoum B. Simmons, pers. comm.

Rattus rattusMus musculus

Flat Island, Mauritius67 Brodifacoum B. Simmons, pers. comm.

R. rattus San Roque, Mexico 70 Brodifacoum &Bromethalin

Tershy & Croll 1996

Rattus exulans Ducie, Pitcairn Group,Pacific 74 Brodifacoum B. Simmons, pers. comm.

Rattus exulans Raratoka (Centre Island),NZ 86 Brodifacoum B. Simmons, pers. comm.

R. norvegicus Stanley, NZ 100 Brodifacoum aerialspread

Buckle & Fenn 1992

Rattus rattus Bird Island, Seychelles 101 Brodifacoum B. Simmons, pers. comm.R. norvegicus Mokoia, NZ 133 Brodifacoum Veitch & Bell 1990

Rattus exulans Long Island, NZ 142 Brodifacoum B. Simmons, pers. comm.Rattus exulans Putauhini, NZ 144 Brodifacoum B. Simmons, pers. comm.R. norvegicus Breaksea, NZ 170 Brodifacoum Veitch & Bell 1990

R. norvegicus Whale, NZ 173 Brodifacoum Veitch & Bell 1990

Rattus exulans Inner Chetwode, NZ 195 Brodifacoum B. Simmons, pers. comm.R. norvegicus Brown, NZ 200 Bromadiolone D. Veitch pers. comm.Rattus exulansRattus norvegicus

Whakaterepapanui,Puangiangi and Tinui, NZ 220 Brodiafacoum B. Simmons, pers. comm.


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Appendix C - 138

R. norvegicus Ulva, NZ 259 Brodifacoum Taylor 1993R. rattus St. Paul, Indian Ocean 800 Brodifacoum aerial

spreadT. Micol pers. comm.

R. norvegicus Kapiti, NZ 2000 Brodifacoum aerialspread

D. Veitch pers. comm.

R. norvegicus Langara, Canada 3000 Brodifacoum Kaiser et al. 1997

Appendix D - 139

Appendix D (McChesney et al. 2000)


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