Gulf Coast Bird Observatory

Linking the Land Birds and People of the Gulf of Mexico

Region

Fall Migration of Raptors – Kites,

Hawks, Eagles, Falcons, and Vultures

Values of Raptor Migration Monitoring

� Counts are efficient, cost-effective method of docu menting regional population trends for multiple species.

� Banding enables tracking studies to delineate migra tory flyways, identify source populations, and document causes of mortality.

� Banding enables health monitoring as well as large- sample studies of basic biology, physiology, and morpholog y.

� Contributes to understanding of migratory ecology.

� Provides superb opportunities to engage the public and promote grass-roots conservation.

Primary Long -Term Raptor Migration

Monitoring Sites inWestern N.A.

Mt. Lorette, ALB

Chelan Ridge, WA

Bonney Butte, OR

Marin Headlands, CA

Kern River Valley, CA

Boise Ridge, IDBridger Mts., MT

Goshute Mts., NVWellsville Mts., UT

Commissary Ridge, WY

GrandCanyon, AZ Sandia &

Manzano Mts., NM

Veracruz, MEX

Corpus Christi, TX

Smith Point, TX

Time frames8-30 years

Managed or co-sponsoredby HawkWatch International

Other organizations

Banding Sites

Dinosaur Ridge, CO

Hawk Ridge, MN

Autumn Routes and Patterns

Continental Geography of Raptor Migration in N.A.Migration Monitoring Network

Primary Concentration PointsLong N-S mountain rangesCoastlines & major lakeshoresMajor river corridorsMajor peninsulas

Commissary Ridge, WYChelan Ridge, WA

Goshute Mountains, NV Bridger Mountains, MT

WellsvilleMountains

UT

Remote Ridge-topSites in the West

Use of Wind -Driven UpdraftsBy Migrating Raptors

wind

As winds collide with the ridge they are deflected upward. Migrating raptors ‘surf’ along these updrafts, proceeding along their way with minimal effort.

Use of Thermal UpdraftsBy Migrating Raptors As the sun heats

the ground, the air above it warms and rises. Migrating raptors effortlessly circle up on these thermal updrafts until they dissipate, then they glide down and catch another thermal, and start the process again.

Corpus Christi, Texas

Smith Point, Texas

‘Easy Life ’On the Gulf Coast

Veracruz, Mexico

Coastline/continental funnelBirds rely on thermal lift

- “kettling” then streaming Variable flight lines

Smith Point Raptor Migration Study

Smith Point

Corpus Christi, TX- US largest flights

Veracruz, Mexico- world’s largest

flights

Gulf Coast Continental Migratory Funnel

Swainson’s HawkMississippi Kite

Broad-wingedHawk

Turkey Vulture

Texas / Veracruz“Superflockers ”

0

10

20

30

40

50

60

70

80

08/17-08/21

08/27-08/31

09/06-09/10

09/16-09/20

09/26-09/30

10/06-10/10

10/16-10/20

10/26-10/30

11/05-11/09

11/15-11/19

Five-day period

Per

cent

of t

otal

cou

nt

1992-1996 mean +/- 95% CI 1999

VeracruzBroad -winged Hawk Fall Activity Pattern

Autumn Daily Rhythm of Migration - Texas

Corpus Christi

0

5

10

15

20

25

30

700

800

900

1000

1100

1200

1300

1400

1500

1600

1700

1800

Hour of the Day

% o

f tot

al c

ount

Smith Point

05

101520253035

600

700

800

900

1000

1100

1200

1300

1400

1500

1600

Hour of the Day

% o

f tot

al c

ount

Values = 1997-2001 mean ± SD

Gulf CoastSpecialties

Harris’ Hawk

Mississippi Kite

Aplomado Falcon

Crested CaracaraWhite-tailed Hawk

Swallow-tailedKite

15,101

11,100

3,645

5,180

2,718 2,576

27,555

59,237

731,94116,287

4,477,057

18,41354,291

68,183

73,776

3,868

~5,000

21,133

Magnitude of Migration at Selected Watchsites

AutumnAll Raptors

HWI Band -Returns and Associated

Western Flyways

Hoffman et al. 2002J. Raptor Research

Satellite Tracking ProgramObjectives

� Improve understanding of migration dynamics

� Identify conservationneeds

� Delineate migratory flyways� Identify migrant source populations� Quantify flyway and territory fidelity

Golden EagleSatellite Tracking2002-2003

Collaborative project begun in 2003 to:1) Develop/maintain continental database and

web-based data entry/access system.2) Produce statistically robust indices of annual

abundance and long-term demographic trends.3) Provide frequently updated, scientifically sound

assessments of the status of migratory raptors.4) Make this information widely available to

participating raptor-migration monitoring sites, the scientific community, conservation and wildlife management agencies, and the public.

The Raptor Population Index (RPI) ProjectA Model Effort to Facilitate Continental-Scale Rapt or Migration

Monitoring and Tracking of Population Trends

HMANA / RPIDatabase System

www.hawkcount.org� Password protected for data entry

and site-profile development� Public-accessible for general

information and data summaries� Redundant back-up system for

secure, long-term data archiving � Rigorous data-use policy for

professional and scientific use according to site preferences

� Linkages with other major avian databases; e.g., Avian Knowledge Network

>5 million records>200 watchsites registered

http://rpi-project.org�Standardized data-collection

protocols

�RPI trend results

�Site-specific, regional, and continental status & trends reports

�Status & trends information packaged for export to participating sites

� In 2010: ability to conduct customized trend analyses on-line, similar to current capabilities of Canadian Migration Monitoring Network and U.S. Breeding Bird Survey

� First major RPI status & trends product� Published June 2008

� Application of new analytical approach� Chapter on migration geography

� Watchsite profiles� Continental autumn migration trends:

1974-2005

� Species-specific conservation status reports

State of North America ’s Birds of Prey

Available at http://www.buteobooks.com - limited supply!

Population Trend

Significant* Increase

Significant Decrease

Non-significant Increase

Non-significant Decrease

*P < 0.05

Trend Magnitude Flight Magnitude

| |trend| < 1 <100/yr

| 1 < |trend| < 5 100-1000/yr

| |trend| > 5 >1000/yr

b

a

a 1997-2005 b 1998-2005 c 1999-2005

a

a

c

American KestrelNortheast Migration Counts1974-2004: -1.6 to -4.5% per yr1994-2004: -3.3 to -8.5% per yrBBS 1976-2003: -1.4%/yrCBC 1976-2003: NE -4.6%/yr, SE -1.4%/yr

Western Migration Counts1980’s-2005: mixed trends1995-2005: -5.9 to -8.6%/yrBBS 1985-2005: -1.7 to -2.7%/yrCBC 1985-2005: -1.5 to -2.5%/yr

Gulf Coast Migration Counts1995-2005: stable to declining (FL)BBS 1995-2005: -0.2%/yrCBC 1995-2005: SE -1.4%/yr

from State of NA’s Birds of Prey (2008)

Migration SiteEducation

Thrill of the Release!!