Importance of the Gulf Coast Region
for Migratory Birds
After the concept of bird banding was introduced to the United States during 1902, modern ornithologists have routinely used bird banding and auxiliary marking to expand our knowledge of avian biology, ecology, behavior, management, conservation, population dynamics, population genetics, and disease transmission. Established in 1920, the North American Bird Banding Program is jointly coordinated by the USGS Patuxent Wildlife Research Center, Bird Banding Laboratory (BBL) in Laurel, Maryland and the Canadian Wildlife Service, Bird Banding Office in Ottawa, Ontario. Each year, approximately 1.5 million birds are banded with nearly 100,000 reports of banded birds received by the BBL. The BBL database contains records of more than 65 million birds banded since 1960 and approximately 4.5 million reports of encountered bird bands dating back more than eighty years.
Given the importance of bird banding data for managing game bird populations, approximately 30% of all banding records are from hunted species. Banded birds harvested by hunters comprise nearly 70% of band encounter reports. In contrast, non-game birds are less well represented in band encounter data although their encounter rates vary and are relatively high for large conspicuous birds but very low for songbirds. Birds tend to be banded at congregation sites and banding data reflect the relative abundance and migration timing at these sites. For game birds, band encounters reflect locations where people prefer to hunt while encounters of non-game birds tend to occur around population centers.
The sizable BBL database provides a wealth of information documenting the importance of regions for migratory birds. One example is the Gulf Coast of Louisiana, known for hosting continentally important populations of wintering waterfowl and other water birds as well as playing a critical role as a stop-over site for migratory birds crossing the Gulf of Mexico each spring and autumn. Birds found in this region migrate and breed throughout the continent, demonstrating the susceptibility of continental bird populations to major changes in Gulf Coast ecosystems.
|The accompanying maps provide examples demonstrating the importance of the Louisiana Gulf Coast region for continental migratory bird populations. The first map shows the banding locations for the 5 species of bay ducks (Canvasbacks, Redheads, Ring-necked Duck, Greater Scaup, and Lesser Scaup) that have been encountered in southern Louisiana. There is a clear connection between Louisiana and breeding waterfowl populations in the Prairie Pothole region of the northern U.S. and southern Canada, with some travelling north to Alaska. Much smaller numbers migrate towards the Great Lakes region, Atlantic Coast, and western states.||
Banding locations for 5 species of bay ducks (Canvasback, Redhead, Ring-necked Duck, Greater Scaup, Lesser Scaup) encountered in coastal Louisiana. Sample size of 2,944 encounter records of ducks banded between 1960-2010.
|The second map demonstrates the importance of coastal Louisiana for gull and tern populations during migration and winter. Gulls breeding in coastal New England and the Great Lakes region regularly appear in Louisiana while tern records tend to be more widely distributed including birds breeding along the southeastern coast of the US.||
Banding locations for gulls and terns encountered in coastal Louisiana. Sample size of 174 encounter records of birds banded between 1960-2010. Herring Gull, Ring-billed Gull, Laughing Gull, Caspian Tern, Royal Tern, Sandwich Tern, Common Tern, Least Tern, and Sooty Tern.
|Coastal Louisiana is clearly an important site for pelican populations throughout the year. For American White Pelicans, Louisiana serves as the wintering area for continental populations migrating from established colonies scattered across central and western North America.||
Banding locations for American White Pelicans encountered in coastal Louisiana. Sample size of 120 encounter records of pelicans banded between 1960-2010.
|In contrast, Louisiana Brown Pelicans form a significant component of the regional population within the Caribbean Basin. Banded pelicans move around the Gulf of Mexico with a few crossing to the Pacific Coast of southern Mexico while others wander north along the Atlantic Coast to North Carolina.||
Encounter locations for Brown Pelicans banded in coastal Louisiana. A total of 11,018 pelicans were banded during 1960-2010 producing 596 encounter records.
|Other birds banded in coastal Louisiana demonstrate different migration patterns. This region hosts significant numbers of wintering Snow Geese that migrate through central North America to nesting colonies in Arctic Canada.||
Encounter locations for Snow Geese banded in coastal Louisiana. A total of 19,647 geese were banded during 1960-2010 producing 3,653 encounter records.
|Wintering American Woodcock from Louisiana are spread across the Great Lakes region to northern New England and the Maritime Provinces of Canada during the breeding season.||
Encounter locations for American Woodcock banded in coastal Louisiana. A total of 4,865 woodcock were banded during 1960-2010 producing 155 encounter records.