Overview
Black-tailed Gull: Large gull with white head, neck, breast, and underparts; light charcoal-gray wings and back; large yellow bill with black ring above red tip; pale yellow eyes with red orbital ring; short yellow legs and feet; long wings; telltale short black tail with white edge.
Range and Habitat
Black-tailed Gull: Nomadic. Primarily Asian straggler, casual to coastal Alaska and northeastern North America, as far south as Virginia; has been seen in San Diego Bay.
Gulls, Terns, Skimmers (Laridae)
ORDER
The nineteen families in the taxonomic order CHARADRIIFORMES (pronounced kah-RAH-dree-ih-FOR-meez) include waterbirds such as auks, sandpipers, gulls, and terns.
FAMILY TAXONOMY
Of worldwide distribution (including the polar regions), the family Laridae (pronounced LAR-uh-dee) encompasses one hundred and two species of gulls, terns, and skimmers in twenty-three genera.
NORTH AMERICA
In North America there are fifty-eight species of Laridae (also known as Larids) in twenty-two genera. Members of this bird family include the graceful, aerodynamic terns, hefty gulls, and the clown-like Black Skimmer.
KNOWN FOR
Larids are known for their affinity for and adaptations to aquatic habitats, the gulls being especially well known for being highly effective scavengers of beaches. Species such as Ring-billed Gulls are also known for having become adapted to habitats made by people that provide similar foraging opportunities such as parking lots and landfills.
PHYSICAL
Larids are web-footed, long-winged birds that range in size from the small and slender, long-tailed terns to the large and hefty short-tailed gulls. In synch with their slender aerodynamic appearance, terns have dagger-like sharp bills, the gulls shorter, stronger bills with a slightly hooked tip to match their tough demeanor, and the Black Skimmer a unique bill with the lower half longer that the upper half.
COLORATION
Adult gulls and terns are for the most part pale-colored birds plumaged in gray, white, and black with dark plumages predominating in the Black Tern and noddy species. Other colors are limited to orange and yellow (in the bills and feet) and pink hues in the plumage of the Ross's Gull and Roseate Tern. Immature gulls of most species cycle through years of a seemingly bewildering number of gray, brown, and black streaked plumages.
GEOGRAPHIC HABITAT
Larids are found near fresh and salt water throughout North America but are most common near large bodies of water. Even marsh nesters such as the Franklin's Gull and Black Tern spend the winter in coastal areas.
MIGRATION
Gulls, terns, and the Black Skimmer are all migratory with the larger gulls migrating short distances to open water and the Sabine's Gull, terns, and Black Skimmer undertaking incredible journeys to the seas and rivers of the southern hemisphere.
HABITS
Larids are very social, highly vocal birds that mostly nest in colonies. Terns dive for fish; gulls pick food off the surface of the water and scavenge beaches for carrion and small animals, The Black Skimmer "skims" the surface of coastal waters, snapping its bill shut when it feels a fish touch its long, lower mandible.
CONSERVATION
While many Larid species have benefited from the presence of people, two tern and one gull species have become endangered. Least and Roseate Terns are threatened by destruction and disturbance of their nest sites on sand bars and beaches while the sharp decline of the Ivory Gull could be related to pollution and global warming.
INTERESTING FACTS
The Arctic Tern migrates more that twenty thousand miles each year on a round trip journey between the Arctic and Antarctic. Populations that breed in the northeast actually do a circle of the Atlantic by flying to northern Europe, heading south along the African coast to Antarctica and then following the American coastlines north.