. . I

THE BREEDING BIOLOGY AND POPULATION DYNAMICS OF THE

BLACK TERN (CHLIDONIAS NIGER ) IN WESTERN NEW YORK

A Progress Report of the 1994 Field Season

Principal Investigators:

Project Cooperators:

Technical Assistants:

J.M. Hickey, Graduate Research Assistant

Richard A. Malecki, Assistant Leader, New York Cooperative Fish and Wildlife Research Unit, Cornell University, Ithaca, NY

D. Pence, U.S. Fish and Wildlife Service

D. Tiller, U. S. Fish and Wildlife Service

D. Carroll , New York State Department of Environmental Conservation

R. Miller, New York State Department of Environmental Conservation

David Seyler Tricia Matte Sonny Knowlton Tanya Swarz Rachel Diebboll

loJ, ~ @ ff n. w r~ r..

L~ ; FEB 6 1995 L I

IROOUOIS NWR

INTRODUCTION

The black tern (Chlidonias niger) nests in freshwater

marshes and reed bordered lakes in its temperate and subarctic

breeding range throughout North America and Europe. In North

America, the species has experienced >70% decline in its breeding

population in the last two decades (U.S. Fish and Wildlife

Service Breeding Bird Survey) . The black tern is currently

considered a migratory non-game bird of management concern by the

USFWS Off ice of Migratory Bird Management and has been proposed

as a candidate (category 2) for listing as a federally endangered

or threatened species. In New York, the species has recently

been reclassified from "special concern" to "endangered" (Mike

Allen pers. comm.).

Historically, in New York, black tern colonies were located

in marshes along the shores of Lake Ontario and the St. Lawrence

River, inland marshes in the western, central , and northeastern

parts of the state, and an isolated site in the Adirondack

Mountains (Carroll 1988). The historic population is not known,

but estimates of 1000 nesting pairs were made in the late 1950 ' s,

at the Montezuma National Wildlife Refuge in central New York.

Today, the statewide population averages < 300 breeding pairs and

colonies in central New York, the Adirondacks, and Lake Ontario

shores near Buffalo no longer exist.

1

•

Loss of breeding habitat through direct wetl and loss is

considered a major contributing factor t o the black tern's

decline (Novak 1992). Breeding habitat suitability may also be

adversely affected by indirect factors such as successional

change, management practices, and degradation of water quality .

At the same time, relatively low reproductive output has

been documented at many black tern nesting sites. Factors

related to nest site selection and availability can influence the

effects of weather, predation, disturbance, etc., on nest success

and other recruitment parameters, although the relationship

between these factors may not be one of cause and effect. The

reasons for low recruitment and their impact on the present

population status of this species remain uncertain.

Less is known about juvenile and adult survival during

migration and wintering, migration routes , and conditions on

wintering grounds. Without a better understanding of the basic

biology and population dynamics of this species, efforts to

improve its recovery will be difficult.

STUDY AREA

The Tonawanda/Iroquois/Oak Orchard wetland complex is

located in western New York, midway between Buffalo and

Rochester, and encompasses nearly 8,000 hectares of federal

2

;

Nest site selection, within six marsh units utilized by

nesting black terns in 1994, was evaluated by comparing a set of

habitat variables (Appendix I) collected from 40 nest site plots

and 41 randomly located non-nest plots sampled from May 31 to

June 17, 1994.

Marsh selection was evaluated by comparing the above 81

plots located within the six nesting marshes to 89 plots randomly

located along a transect run through a representative section of

each of 15 of 31 marshes not used for nesting in 1994. Twelve

drawndown units and four other marsh units were not included in

the sampling in 1994. A subset of habitat variables were

collected in these plots (Appendix II). Additionally, aerial

photographs were taken in early June.

The goal of the habitat data analysis was to find the best

fit model to explain the relationship between the response

variable (ie, presence/absence of a nest or nest marsh/non-nest

marsh) and the predictor variables (measured habitat variables

from plots). Logistic regression with stepwise selection was

used to find this model because of the binomial nature of the

response variable for both levels of selection (SAS Institute

Inc. 1989, Manly et al. 1993).

For nest site selection, the response variable was the

presence (nest site) or absence (non-nest site) of a nest. Nine

habitat variables were selected for the regression analysis.

4

These were :

1) cover type (CTYPE) - dominant life form (ie , open water,

emergents, scrub/shrub, forested) (Cowardin 1979)

2) dominant species (SPECIES) - standing vegetative species with

highest relative percent cover by ocular estimate

3) density (DENSITY) - ocular estimate of density of dominant

species categorized as 1-very dense, 2-moderately dense,

3-sparse

4) average vegetation height (HEIGHT) - average of four cardinal

point ocular estimates of standing vegetation per plot

categorized as 1 = ::::: 25cm, 2 = 26-50cm, 3 = 51-lOOcm, and

4 = > lOOcm

5) , 6), 7) horizontal cover at 0.2 m, 0.5m, and lm, above water

level (HCOV2), (HCOVS), (HCOVl), respectively, - average of

four cardinal point ocular estimates at 4m from plot center

looking in to center, measured with black and white

checkered density board (Hays et al. 1981), and categorized

as 1 = ~ 20%, 2 = 21-50%, 3 = 51-79%, 4 = ::::: 80%

8) average water depth (H20) - average of four water depth

measurements per plot in nest marsh plots and five

water depth measurements per plot in transect plots,

using a graduated rod

9) interspersion of vegetation : water (INTER) - ocular estimate of

distribution of vegetation to water within the plot, and

5

classified as one of nine possible categories where "low"

interspersion includes categories 1-3, "medium" includes

categories 4-6, and "high" includes categories 7- 9 (Appendix

I) •

For marsh selection , the response variable was marsh with

black tern nests (nest marsh) or marsh without black t ern nests

(non-nest marsh) . Five habitat variables were selected for the

regression analysis , using the same definitions as above, and

these were: 1) cover type , 2) dominant species, 3) average

vegetation height, 4) average water depth, 5) interspersion of

vegetation to water.

Nesting Effort and Success

Observational surveys for breeding activity were b egun on

May 10, 1994 , the black terns having arrived to the study site

one week prior. All 37 marsh units within the complex had a

minimum 20 minute sur vey completed by the end of May . Several of

the units were resurveyed periodically once nesting began . Nest

searches by foot and canoe were started on May 31 , 1994 , once the

majority of the nesting had started. Each nest found was marked

with a flagged stake , nest contents recorded, and incubation

stage was determined following Hays and Lecroy (1971) by floating

each egg in a beaker of marsh water. Nests were rechecked at 7-

6

10 day intervals until terminated and a fate determined as either

hatched, abandoned, or destroyed. Nests were classified as

"successful" if at least one egg was confirmed hatched, "probable

success" if no eggs were confirmed hatched, but nest was intact,

nest appeared used (ie, soiled with droppings), and/or mobbing

by adults was intense when at nest site. Nests were classified

as ''unsuccessful " if nest or eggs were missing or destroyed

before expected hat ch date, or eggs were abandoned in which eggs

failed to hatch past expected hatch date. Nest locations were

plotted on 1:12000 aerial photographs .

Fledgling Success

Fledgling counts were performed opportunistically during the

month of July, with a full survey of all marsh units completed on

July 18, 1994.

Adult and Immature Movements

To monitor movements of adults and immatures, radiotelemetry

was the preferred method of choice. Due to the colonial nature

and intense mobbing behavior of black terns in the breeding

colony, telemetry lends itself well to minimizing disturbance so

behavioral responses are not abnormally invoked . Additionally,

7

it was necessary to mark the birds to monitor s urvival and causes

of mortality.

The transmitters were attached to #2 USFWS bands using a

copper wire and green epoxy (Morris and Burness 1992 ) and built

by Holohil Systems Ltd. of Woodlawn, Ontario. The total package

weighed 1.35g with a battery life of three weeks . The

transmitter range tested on flat open ground was 1.6 - 2. 0 km.

In the field, the range was approximately 0 . 8 - 1.6 km. Testing

of the telemetry performance and range from the air revealed the

best flying altitude was 0.6 km - 0 . 9 km above mean terra i n at

which the signal was received at nearly 3 km.

A passive , drop/walk- in trap made of hardware cloth was used

to trap adults during the late stage of incubation (Mazzocchi and

Muller 1993) . Immatures were caught using a semi- drive technique

near the nest site prior to fledging . Adults and immatures were

weighed to the nearest 0.1 g to ensure that the transmitter

weighed < 3% of total body weight for adults and < 5% of initial

body weight for immatures. The immature black terns had to be

about 10 days old or at least 38-40 g before this limit was

reached . The transmitter weight was 2.4% of the total body

weight of the lightest adult tern . Superglue™ was used to repair

cracks that formed in the epoxy upon band application, although

the radio contents were designed to remain protected in the event

cracking occurred .

8

Tracking of transmit t ered b i rds was done by foot, canoe, and

vehicle using hand-held 4-element Yagi antennas and a directional

antenna mounted to the vehicle . Each bird was located three

times a day . The adults were monitored for one-hour periods with

two people set up along the presumed flight path. One of the

adults was also monitored from a concealed location near the nest

site, with a second person placed away from the nest site to

determine where the adult foraged. The early alarm response of

the birds made approaches within the marsh very difficult.

Knowledge of the transmitter range and performance in varying

conditions enabled us to determine the approximate locations of

the birds when located. Visual sightings of perched and flying

birds were often possible. Triangulation procedures were often

difficult because birds were moving or vegetation dampened the

signal such that adequate bearings from more than one location

were not possible. A single aerial survey was conducted to test

the transmitter range and make an attempt to locate a missing

bird .

Full nest enclosure traps made of one inch black plastic

mesh were placed around two nests during incubation to assess the

feasibility of monitoring and capturing chicks. The nets had a

7m radius and were extended 15.2 cm above and below the water

level and secured with green aluminum stakes that were flush with

the top of the net.

9

RESULTS AND DISCUSSION

Habitat associations and preferences

Nest site selection

For nest site selection, the regression model selected

horizontal cover at 0.2m (HCOV2) and O. Sm (HCOVS) and

interspersion (INTER) as the best predictor variables for the

presence of a nest within a nesting marsh. For the model of best

fit, the combined effects of these variables were significant

(p=0.0007) . Nest plots and non- nest plots were correctly

classified 70 . 0% and 73.2% of the time, respectively . The

overall correct classification rate for all plots was 71.6% using

this model . The regression equation for the model was :

logit (P) = -0 . 9396 + 1 . 3852(HCOV2) - 1.9420(HCOVS) +

0.2447 (INTER),

where (p) is the probability that a site contained a nest.

The probability (p) is the predicted probability the "event"

(nest site) occurs for specific values of the predictor habitat

variables entered. This is calculated as:

{p) = e (logit p)

1 + e 1109it Pl

10

The coefficients in t he regression equation denote the slope

of the relationship of each habitat variable to the other

variables, and have a magnitude and a direction (positive or

negative). The probability of the presence of a nest increases

with increasing values of the logit (p). The HCOV2 was relatively

large and positive, indicating large values of HCOV2 were

associated with nest sites. The data showed that 80% of the nest

sites had 21%-89% horizontal cover at 0.2m off water compared to

non-nest sites in which 43.9% of the plots were in cover < 21% .

The HCOV5 coefficient was relatively large and negative,

therefore, nest sites would tend to fall into the lower cover

classes at 0.5m off the water . The data showed that 50% of the

nests were in cover <21% , and 90% of all nests were in 50% or

less horizontal cover at 0.5m off the water. This is probably

related to the height of the vegetation and the stage of growth,

being more sparse near the tops of the sterns, as in newly growing

bur-reed (Sparganium spp.). Bur-reed was the dominant species in

30 out of 40 (75%) of the nest sites . The non-nest sites showed

58% of the plots were in cover <21% , as well as , 24% in cover

51%-79%, indicating more variability in the amount of cover at

0.5m. Most of the nest site plots had 21 - 79% horizontal cover at

0.2m and < 50% cover at O.Sm. Overall, the data suggest nest

sites were located where there was moderate cover near nest

11

level, possibly for better concealment, bu t more open cover above

the nest, possibly for predator detection.

Interspersion was ranked in increasing order from 1-9 and

72.5% of the nest sites occurred in the "medium" interspersion

categories. In comparison, only 39.0% of the non-nest sites

occurred in the medium interspersion categories, and in fact,

non- nest sites were distributed more evenly across all levels of

interspersion (low, medium, high) . This may explain why the

coefficient for this variable is not large, but relative to non­

nest sites, interspersion in nest sites in generally higher,

again indicating the importance of a cover component for nest

site selection . The feeding and house-building activities of

muskrats create openings within the vegetation influencing the

patterns of interspersion, as well as , providing substrates for

nest sites.

Analysis of the six variables not selected by the model

showed more similarity between plots within a nesting marsh.

Water levels are controlled by unit with water control structures

and are more uniform throughout the marsh unit. Most of the

nesting marshes were dominated by emergent vegetation,

specifically bur-reed. Bur-reed was dominant in 46 . 3% of non­

nest plots and 75% of nest plots as compared to cattail (Typha

spp.) which dominated 31.7% of non-nest plots and 17 . 5% of nest

plots.

12

Marsh selection

The regression model for marsh selection included all five

habitat features entered: 1) cover type, 2) dominant species,

3) average vegetation height, 4) average water depth, and 5)

interspersion of vegetation to water, as key variables to best

predict a marsh used by nesting black terns. For the model of

best fit, the combined effects of these variables were

significant (p=0.0001). Nest marshes and non-nest marshes were

correctly classified 75.3% and 69.3% of the time, respectively.

The overall correct classification rate for all plots was 72.2%

using this model . The regression equation for the model was:

Logit (p) = -0.5188 - 0.0416(CTYPE) - 0.0326(SPECIES) -

0.8259(HEIGHT) + 0 . 0152(H20) + 0 . 5075(INTER),

where (p) is the probability that a marsh will be used for

nesting.

The coefficients for CTYPE, SPECIES, and HEIGHT were

negative which means nest marshes were associated with low values

of these variables. For CTYPE and SPECIES, the emergent

vegetation cover types were coded 1 and species were coded from

1-10 as compared to shrubs and trees which were coded using 20's

and 30 ' s , respectively. This means marshes with higher

occurrences of shrub/trees in plots would decrease the

probability of classifying a marsh as a nest marsh . Only 2.5% of

13

the nest marsh plots were classified into cover types of shrub or

forested compared to 28.0% of the non-nest marsh plots. At the

species level, 60.5% and 24.5% of the nest marsh plots were

dominated by bur-reed and cattail, respectively. Only 4.9% of

the nest plots were open water. In non-nest marshes, 7.8% and

30.3% of the plots were dominated by bur-reed and cattail,

respectively. 22.5% of the plots were in open water and 39.3% of

the plots were classified into the shrub/forest categories. This

suggests non-nest marshes have a greater proportion of open

water, cattail, and woody vegetation compared to the nest marshes

which are primarily dominated by less open water and more

emergent vegetation.

HEIGHT was similar in its effects with CTYPE and SPECIES .

In general, average height of vegetation in nest marshes was 26 -

50 cm in which 50.6% of all plots were classified. This compares

to only 9% of the non-nest marshes in this height class . The

majority (56.2%) of the non-nest marshes were in the tallest

height class of > lm . This is probably a result of not only the

woody shrubs discussed above, but also the dense, old permanent

cattail stands encountered frequently. As noted above, 30.3% of

the non-nest marsh plots were dominated by cattail.

H20 and INTER had positive coefficients suggesting that nest

marshes were classified with relatively higher values of these

variables. Average water level for nest marshes was 52.0 cm

14

(SE=25.3) and 43.8 (SE=36 .2 ) for non-nest marshes, indicating

more variability in water levels in non-nest marshes .

The analysis of interspersion was similar to the analysis

done for nest site selection . Nest marsh plots were most

frequently (55.6%) classified in the medium intersperion

categories, compared to 31 . 5% of the non-nest marshes. Non-nest

marshes were most frequently (44.9%) classified into the low

interspersion categories. The high interspersion category

occurred almost equally frequently between nest marshes and non­

nest marshes. This analysis suggests, again, that an

interspersion of 50:50 vegetation to water seems to be

significant in nest marshes used by black terns.

Substrate Use

Of 49 nests, 25 (51.0%) were built on old muskrat houses, 12

(24.5%) on muskrat feeding platforms for a total use of muskrat

structures of 75.5% in 1994. Other substrates used were floating

mats (20.4%) and grebe nests (4.1%).

15

Nesting Effort and Success

A minimum estimate of 38 nesting pairs was determined for

the 1994 season . A total of 50 nests were located and marked

throughout the complex as follows :

Marsh Unit # nests

Iroquois NWR : Cayuga 13 Knowlesville 7

Tonawanda WMA: Paddy III 6 Ruddy 3 Wood 7

Oak Orchard WMA: Windmill 14 Total 50

Four nests classed as "probable" successes were excluded

from nest success calculations. Apparent nest success (the

successful hatch of at least one egg) was 56.5% . Using the

Mayfield method (Mayfield 1961, 1975, Johnson 1979) of nest

success, daily nest survival was 0.9623 with a 95% confidence

interval of 0.9457 to 0.9788. Total survival was 0 . 4458 or

44.6%. Hatching success (proportion of all eggs laid that

successfully hatched) was 37.5%. Average clutch size was 2.87 .

The nest data is summarized as follows :

Total Known Prob. Known & Total Total Total nests Success Success Prob. eggs chicks known

Failed laid hatched fledged

50 26 4 20 136 51 19

16

Fledgling success

A maximum count of 19 fledglings resulted in a fledging

success rate (proportion of number fledged to number of eggs

successfully hatched) of 37.2%. A recruitment rate (number of

fledglings produced per pair) was calculated to be 0 . 5.

Adult and Immature Movements

Of nine transmitters used, two failed prematurely, possibly

due to structural or water damage as a result of the cracked

epoxy. No transmitters failed that were repaired with

Superglue™. The transmitters were found to last for nearly four

weeks before battery failure.

Four adults were trapped and three of these fitted with a

transmitter. The fourth adult was trapped in Wood marsh and

found to be a retrap that was banded in Wood marsh as a chick in

1991. Upon release the adults flew about picking at the

transmitter with their bill . This was observed several times

over the next several weeks. The leg hung down slightly below

the rest of the body, but this seemed to be minimized as time

progressed. Except for picking at the transmitters, there were

no other abnormal behaviors observed related to the transmitter

and the birds flew, fed , incubated, and perched without apparent

difficulty. Close monitoring of one of the nests revealed the

transmittered adult to make repeated successful foraging runs to

17

feed the nestlings . The trans~itters worked well on the adults,

fit the leg well, and remained in position with the antennae

oriented posteriorly.

Six immature pre-fledged terns were transmittered . The

copper wire used to secure the unit to the band removed nearly

lmm of the inside diameter of the band making the band fit much

tighter on the fuller legs of the immatures as compared to the

adults. The transmittered immatures successfully fledged on or

near the expected fledge date. They were observed to perch, fly,

and feed similar to non-transmittered birds without apparent

affect from the transmitter. They were never observed to pick at

the transmitter as the adults did . All young perched for long

periods with brief flights during the first week or two of

fledging. The transmittered juveniles did not appear to perch

more or fly less than the non-transmittered birds . The following

account summarizes the telemetry findings:

Bird #1 - Adult Date banded : 6/19/94 Weight : 59.0 g Location: Wood - Nest #47 Date terminated: 7/19/94 Comments: Monitored at nest several times for one-hour periods. Never located beyond marsh boundary (within 0 . 8 km), although it is believed to have travelled beyond this.

Bird #2 - Adult Date banded: 6/19/94 Weight: 61.0 g Location: Cayuga - Nest #28 Date terminated: 6/24/94 Comments: Transmitter failed. Bird seen several times after this.

18

Bird #3 - Adult Date banded: 6/21/94 Weight: 56.0 g Location: Windmill - Nest #37 Date terminated: 7/27/94 Comments: Foraged many times in Oxbow marsh approx . 0 . 8 km away and eventually brought fledglings to this site as a day roost and returned to Windmill nest area to roost at night.

Bird #4 - Immature Date banded: 6/20/94 Weight: 38.5 g Location : Knowlesville - Nest #30 Expected fledge date: 7/3-7/5/94 Confirmed f l edged: 7/7/94 First date found beyond nest marsh: 7/14/94 Date terminated: 6/25/94 Comments : Transmitter failed. Confirmed fledged after signal failed and found in Cayuga marsh, about 8 km way one week later .

Bird #5 - Immature Date banded: 6/26/94 Weight: 44.5 g Location : Cayuga - Nest #26 Date terminated: 7/1/94 Comments: Found dead at nest site prior to fledging. Cause of death felt to be from complications during transmitter attachment.

Bird #6 - Immature Date banded: 7/13/94 Weight: 49.0 g Location : Wood - Nest #47 Exp . fledge date : 7/23- 7/25/94 Date terminated: 7/19/94 Confirmed dead: 7/21/94 Comments: Off spring of bird #1 . Depredated by a mink just days prior to fledging, as indicated by damaged transmitter found near nest site where banded.

Bird #7 - Immature Date banded: 7/14/94 Weight: 45 . 3 g Location: Wood - Nest #45 Exp. fledge date: 7/26/94 Confirmed fledged : 7/28/94 First date found beyond nest marsh: 7/31/94 (Cayuga) Date terminated: 8/15/94 Comments: Successfully fledged. Utilized Wood to perch and feed in day and began to roost in Cayuga marsh, 3.2 km away .

19

Bird #8 - Immature Date banded: 7/14/94 Weight: 65 . 0 g Location: Windmill - Nest #37 Exp. fledge date: 7/17 -7/19/94 Confirmed fledged: 7/18/94 First date found beyond nest marsh : 7/22/94 (Oxbow) Date terminated: 7/29/94 Comments: Sibling of bird #9 and offspring of bird #3. Roosted in Windmill near nest site and used Oxbow, 0.8 km away, for day activities. Lost contact with bird just hours after several osprey flew into Oxbow to perch upon release from a hacking project. Black tern never relocated on refuge. An aerial attempt was made over entire refuge, along part of the Lake Ontario shore and down the northern end of the Niagara River , but not found.

Bird #9 - Immature Date banded: 7/14/94 Weight: 61.0 g Location: Windmill - Nest #37 Exp. fledge date: 7/17 -7/19/94 Confirmed fledged: 7/18/94 First date found beyond nest marsh: 7/22/94 (Oxbow) Date terminated: 8/15/94 Comments: Sibling of bird #8 and offspring of bird #3. Followed same pattern as bird #8 , but it was found 24 hours later in Wood marsh, 14.5 km away, after osprey release. It had joined up with other black terns utilizing this marsh and also roosted in Cayuga at night, used Wood and Ruddy during the day, 3 . 2 km away, and used Cinnamon in early evening, 0.8 km from roost site.

The nest enclosures were successful at least until the

chicks were 5-7 days old. At this age, they began to reach the

perimeter of the net upon approach, but sat quietly hidden in the

vegetation without struggling to get through the net. The

enclosures were removed when the chicks were 5-7 days old.

20

--··------ ------------

1995 Field Season

Habitat Associations and Preferences

The habitat sampling was complete in 1994. Transect surveys

on the marshes not sampled in 1994 may be completed if additional

data is desired. Additionally, another smaller sample of nest

sites and random plots may be collected to compare habitat use

between years . A smaller subset of habitat variables defined

from the analysis could be collected.

Nesting Effort and Success

Similar procedures and data collection will be repeated next

year. Due to the small size of the colony, attempts to find and

monitor all the nests to completely assess nest success of this

colony is desired.

Pre-fledging and Post-fledging Survival and Dispersal Movements

No adult terns will be transmittered in 1995. Pre- and

post-Pre-fledging survival and movements of immature black terns

will be evaluated using radiotelemetry. A new, smaller

transmitter is now available, weighing only 0.73g, with a battery

21

life of two weeks. The additional epoxy required to waterproof

the unit and the weight of the leg band will result in a total

weight of about 0.75g. The transmitter would weigh 7.5% of the

initial body weight if attached in the first day or two after

hatching based on 10 g average weight of newly hatched chicks

(Bailey 1977). The chicks move only within a meter of the nest

during the first few days after hatching , so the initial added

weight may not severely interfere with their movement needs

and/or affect survival. The leg band is the best method of

attachment due to the preening capabilities of the adults.

The immatures will be divided into two groups. Ten to

twelve chicks will be randomly selected from each of the nesting

marshes for Group 1 during 1-3 days post hatch, transmittered,

and monitored to 12-14 days post hatch . In order to minimize the

number of nests subjected to disturbance, two chicks per nest

will be selected when possible. These chicks will be fitted with

a transmitter attached to a more easily removable plastic band.

The transmitter can now be attached with fishing line so the

inside diameter will remain nearly normal for the size of the

band selected. The antenna on these would be removed to decrease

the chance of the chicks getting caught in the vegetation. This

would significantly reduce the range of the signal to less than

46 meters. Recapture of the surviving chicks would enable us

then to remove the first transmitter and replace it with a fresh

22

transmitter to monitor the post-fledge period for chicks in Group

2 .

Group 2 will consisx of another 10- 12 chicks selected from

surviving birds in group 1 plus any additional birds caught using

the drive techniques. Group 2 will be transrnittered and

monitored from 14 days post hatch to one week post fledge. They

will be fitted with a more permanent transmitter with a full

length antenna.

Enclosure nets will be placed around a random sample of 5-10

nests without marked birds during incubation stage to compare

survival rates between transmittered and untransmittered chicks,

at least during the first week post hatch .

23

LITERATURE CI TED

Adams, D. J. 1990. Population status and breeding ecology of the black tern (Chlidonias niger} at the Iroquois/Tonawanda/Oak Orchard compl ex, 1990. Unpublished report. St. John Fisher College. 66 pp.

Bailey, P.F . 1977. The breeding biology of the black t ern. M. S . thesis, University of Wisconsin, Oshkosh. 67 pp.

Carroll, J . R . 1988. Status and breeding ecology of the black tern (Chlidonias niger} in New York . Nongame Unit, Division of Fish and Wildlife, NYS Dept . Envir. Conserv. , Delmar, NY . 20 pp.

Cowardin, L . M. , V. Carter, F.C . Golet, and E.T. LaRoe. 1979. Classifi cation of wetlands and deepwater habitats of the United States . U. S . Dept . Inter ., Fish and Wildl . Serv ., Washington, D.C . 131 pp.

Hays, H. and M. Lecroy. 1971. Field criteria for determining incubation stage in eggs of the common tern . Wilson Bull. 83 :425- 429 .

Hays , R.L ., c. Summers , and W. Seitz . 1981. Estimating wildlife habitat variables . U. S . Dept. Inter . , Fish and Wildl . Serv. , Washington, D. C. 105 pp.

Hickey, J.M . 1992 . 1992 population status of the black tern (Chlidonias niger} at the Tonawanda/Iroquois/Oak Orchard complex. Unpublished report. Bureau of Wildlife , NYS Dept . Envir. Conser . 45 pp.

Johnson, D. H. 1979 . Estimating nest success : The Mayf ield method and an alternative. The Auk 96:651-661.

Manly, B., L . McDonald, and D. Thomas. 1993 . Resource selection by animals . Chapman Hall , New York. 177 pp.

Mayfield, H. 1961. Nesting success calculated from e xposure. Wilson Bull. 73 : 255-261 .

1975. Suggestions for calculating nest success. Wilson Bull . 87 : 456-466 .

24

Mazzocchi, I.M . and S.L. Muller. 1993. Black tern (Chlidonias niger) survey in New York State, 1992. Division of Fish and Wildlife, NYS Dept . Envir. Conserv. 21 pp .

Morris, R. and G. Burness. 1992 . A new procedure for transmitter attachment : Effects on brood attendance and chick feeding rates by male common terns. The Condor 94:239- 243 .

Novak, P.G. 1990 . Population status of the black tern in New York State - 1989. Division of Fish and Wildlife, NYS Dept. Envir. Conserv. 33 pp.

Novak, P.G . 1992. Black tern, Chlidonias niger . Pages 149-169 in K.S. Schneider and D. M. Pence, eds. Migratory nongame birds of management concern in the Northeast. U.S . Dept . Inter . , Fish and Wildl. Serv . , Newton Corner, Massachusetts. 400 pp.

SAS Institute , Inc. 1989. SAS/STAT User's Guide, Version 6, 4th Edition, Volume 2, Cory, NC: SAS Institute Inc. 846 pp.

Seyler, D.A . 1991. The status of the 1991 nesting population of black terns (Chlidonias niger) at the Tonawanda Wildlife Management Area . Unpublished report. Bureau of Wildlife , NYS Dept . Envir. Conserv. 38 pp.

1993. The nesting success of the black tern (Chlidonias niger) at the Tonawanda/Iroquois/Oak Orchard wetland complex in 1993. Unpublished report . Bureau of Wildlife, NYS Dept. Envir. Conserv. 20 pp.

25

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Figure 1.

.. .. .. .. .. TONAWANDA WILDLIFE MANAGEMENT AREA

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prepared by the Habitat Inventory Unit

BLACK TERN SAMPLE PLOT DATA SHEET APPENDIX I

· J Jni t name. ___________________ · Date_______ __ Time start: Personnel Time finish : -------

' \ Nest : Present ; 1., .~~ent . . ... Approx. location (x,y coordinate distance in yards from landmarks)=-------------~

Azimuth: Point #1. _____ 0 Point #2. _____ o Point #3 ______ 0

PLOT DATAr Vaqetation Typ!/Heiqht/Horiz .cover/ Wa ter Depth

A Dominant 8 cover

' P, type e c t

N

E

s

w

c

Ava ht. classes: 1 · < 25 cm 2 - 25-50 cm 3 • 50-100 cm

a 4 m

Avq. '5 Horiz. Ht. Cover

class (1-5)

0.2m/0.5m/lm

4 · 100-150 cm 5 · > 150 c.m

Water depth

(cm)

% Horiz. cover 0 - no cover 1 - 20 % 2 - 40 %

classes : 3 . 60 % 4 - 80 % 5 • 100%

# o~ other potential n .. t• • itea : p.f .,,,_ __ ,,_ _____ house.,._ _______ _ f l oatinq veq. mat. _______ mud mound.._ _______ other _______ _

loq ___ _

snaqs: (dead standing wood or other objects visible above water level suitable for perching, excl. potential nest 'ites · within plot):

NONE !

# within 4 m radius-------­# within 12 m radius

Avg. height (S,M,T)

. Height classes : Short • < 1. 0 m jiedium -- 1.1 - 2.0 m !,all - > 2 . 0 m

Distance to nearest anaq [within plot (ea t. if beyond 4 m)]

Avg. size (l,2,3)

Size classes (avg. dia. ): 1 · < 10 cm 2 · ll-20 cm 3 - > 20 cm

Aspect: N S E W

Describe (type & approx. ht [cm}) __________________ _

% Interspersion (% ve9:%H~O) [circle one):

A · < 20% B - 20:80 c . 30:70 D · 40:60 E · 50:50

60:40 G - 70:30 H · 80:20 I · > 80%

29

Small water pool• · open water area• that inter••ct plot that are > 3 m in diameter axcludioq large open water bodie•1

# (circle one): 0 1-2 3. 5 >51

Distribution (circle one): scattered .• -. ~ \;. , ~ ... !~ . · . . t .... . ) : : '

·' Di11tanca to ·neare•t 11mall water pool (a11t. > 4m) . . - ~ · :: ..

clumped (Aspect: N S E · W)

A•pect1 N s E w

Dominant 11tanding _vaqetative 11pecie11 within plot, relative cover, and relative den11ity: . . -: . :~ .: . .; . .

Speci~s Relative cover (\) Relative density (l,2,3)

#1·----------------------------#2. ________________________________________ __ #3 ___________ _,_ ______________ __

TOTAL REL. \ COVER

Total. \ floatinq cover·-------------­/

Species Rel. cover (\) #1 #2·---------------

# 3---------------TOTAL REL. \ COVER =°"" 100\

100%

Relative density:

l · very dense 2 · moder. dense

3 · sparse

Di11tance to nearest dominant cover type adqe plot (eat. > 4 m) __________ N s E w

NEST DATA:

Nest contents: ___________ __ Incubation data:

Staqe (a-d)

Eqq #1 ..... ------------­Eqq #2---------------Eqq #3 _____________ ___

, .. Hiight of nest bowl above H20 (mm)=-------~---

-Bd'Wl moisture (circle): dry moillt very moist

# mm exposed (e-1)

wet other:

Nest substrate type (circle one) and composition: ______________ __ '

feed platform: fresh mixed old.__ _____ _ house: (active/inactive) ht. of top above H

20 (cm) ______________________ _

loq . mud mound floatinQ mat . (describe) _________________________________________________ __ other (describe) ______________________________________________________________ __

· substrate size (l x w) (cm) ______________________ ___

Distance to nearest veqetation (cm) _____________ Aspect (circle all) N s E W · I.D. __________________________________ ___

;/ # 11idas 11urroundad by veqatation withi.n 1 m (circle): 0

Distance estimates (yda.):

Nearest black tern nest. _________________ _ -· Nearest larqe open water body _____________________ __

Nearest marsh edge~--------------Type. _______________________ __

30

1/4 1/2 3/4

Aspect (circle all) :

N N N

s s s

E E E

w w w

1

MARSH HABITAT SURVEY P'ORM ' .. ....... .. . ... . ,. ' ·' ·'· ..

/ Un it name_...._ _ _ . ' ' , ·

~---· - - - :=-~-~.~··· ·4\., .. - ~ate ___ -"-------· Time ata~t :_"' .-9_.,_. _. _____ ...:_....;'•:___

Unit size (ha) _______ _ --:r~-:..· · ; j".lJ., Time4 f iniah: i. ·~"::'.:: : ;._...;... ___ ..;_;;_;:..:..; __ ~ Tran•ect - start point: f'-:> • f';;J "If ,..~ • r.11 '· /Of' /b1NT.~~$.i ) 10'~ "• .. __ _...._ ........ _ __..__ ........ _..:.;_ ___ -J,[..._ _ _:....:..::.:..:....::.:.~v~.:!:.::::;,.,!....:..~:__:_ _____ _

stop po int: _________ ......:;A~O~n:..:....~<_-__ ....;..:.L ....;':....;:_....;·:__ __ . ,;___)....;;~· ~·~~-r-··__:O:___:C_-~:~;~, ~·--.:..._-----

direction of travel: _______ _ Approx. length ~ ( yda )'!'_ ·! ___ . _"!_~_._._· •_1 __ i_!_. __ _

I .. r 4l :.,,, -.- '

. Random -points - - water control- structur·e ..

Point #

1

H20-depth~- --Stru-cture (cm) #

-Hit>- deptn- -.­(cm )

".2> . ~t 1.;v.4A!"-r' -·-· . --A i/C.--rll• 5/71', Ct.~S;; -' -· - -

I I

I

~:-JEL' ::;::' -~· cs:l~ •e:-, •• - · •• ;_::_o.;_·-:_.';,.·~ • .!'-··_:'_-..·. j I ''-~~2--+-------~~---~---"'"'-~--+-~--~-- -- ----~- 1--------++-----,,....:::.:.....:. __ __j rr

1 ••,._ •

3 ;: ! ;: ;;,.- :J -j U '{ l 'J j L ":' ! "::'I - - . • • _

4 ~·: ~ • G • ~ . ·.

...:ic.--..:":...-·.:=:--~~ ..... '"'-' .......... .. : u.:..- ~ -....... 5 ...z7.,:.a._• .,..u·it-:·.~..zo\.-~ ~

ft---:--:-~-t---:'----:-:---:--1~---:------.--~~-""!":"'~---....... ---------_,:;_~-·~·~· -~:;_.:_:•:__• __;··~·__; __ I ~ rl--• -~-! - ·; ; ,;, ;•·-' I

6

7

8

9

10

Total

Avg :'= H20

depth (cm )

MUSICRAT SIGH:

.1nr"* • ........

---~ - . ... " ......

·- ·.· ·- .

, Animals seen ( eeYAt)

·- ... _ ... ..r-- ~ ·-·

.,. • L. . , . • • .': ... .. ,._

• , ••: .. l.

Houses (count) ________________ _

Feed platforms (est .): few · several

Bank holes (est . ): few · several

many

many

'E'8tl.mate Of total abaudauee of'1ill sign : Sparse

" - IV'~ ~ 4• t'G /.0. () d~NcJ-r11 / - ~ ~.,,- (;A'J

~ 61 $9 -s-a <t;h?

~ So-/~• CA? 31

!:". ~::· . • ' .:. •

. •. · :..:· ::-:.::r./

a.4~:: .. -:. • ..: ·-u -· '•• ... . -,.

Mode r . -Jl.bu~t

..... ........... --.... --.. l • •

VEGETATION:

_ __ Dom_i_n~nt ___ c_o'!~r. type: ~ Emer9ent __ Forested Mixed E/ F . Other_....;..;.. ____________ _

-· In~~-~sp_er_l!.i~n (\vegz\H20)'. (circle one):

A - < 20\ ~ a ·~·~OISO ~b ~ ~30:70 .. . ... __ ... ~ __ .. ______ ,_____ ··-- ---- . 0 40:60 E - 50: 5 0 _

F - 6~.:_4_0 __ ~ .. : . 1q_:}Q ____ H - 80:20 I . . - > 80\

Total \ cover in emer9ent: .r. • ·- .• ... - .. - - - -~ - -·-- \ ........ ' . . .:. .

Relative \ cover and relative density of 1-3 dominant cover types: --= .· ... .. - - •. ..:. - ~;::-:: - ' • -

. Species-- . Relative cover(\) Relative density Cl,2,3>

"' #1 _________________ _

#2 - -···- -.· ;J .. - - -i;. ---:-~ . - ::: :

#3 ____________ _

·-::, -r'." . - /. / o, • , ~J ,. 4.. -1 .,.• .._, .:>

,. ·.~ ;

Rel. \ -cover: Rel, density: l - abundant -- -- ·- - -·-- "

2 - moderately abundant ., . 3 - sparse

SNAGS (dead standing wood or other objects above water level suitable for perching ) :

Abundance (circle): none 1-- sparse

Avg. diameter (circle): 1 - ~ 10 cm · · 2 - 11-20 cm

3 - > 20 .·cm

moder . abundant

Distribution (circle all that apply)"! ___ · "Edge Scattered

OPEN WATER:

Large open water areas:

'.; -· . -· .. Middle Cl umped .. "- -- - ·--

Present .. . .. Ab t

;;_-=- • sen .. ,, .. " - ·

Distribution: Edge

Middle

abundant·

-- - -· .. -· ·-·

Scattered

· Clumped

Approx. distance to nearest l~rge open water from middle of emergent cover (yde.): ____ _

COMMBHTS:

. : • !. ::·!

32