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Caspian Tern Sterna caspia


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Caspian Tern, summer
credit: Mdf/CCSA

© Lang Elliot/ (audio)

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Family: Laridae, Gulls and Terns view all from this family

Description ADULT summer Has pale gray back and upper wing and mainly white underparts. In flight, however, note that upper surface of primaries is marginally darker than rest of upper wing, and trailing margin of primaries is darker still; from below, primaries are blackish. Legs and cap are uniformly black. ADULT winter Similar, but cap is streaked black and white, darkest below eye, rather than uniformly dark. JUVENILE Similar to winter adult, but with paler bill and subtle scaling effect on back and upper tail.

Dimensions Length: 19-23" (48-58 cm)

Habitat Very locally common breeding species (mainly May-Jul), nesting in colonies on gravel or sand islands and bars in or near freshwater lakes and rivers rich with fish, and coastal estuaries and lagoons. Coastal birds seldom feed far from shore. Disperses and moves south outside breeding season, wintering on Gulf coast, and coasts of Central and northern South America.

Observation Tips Typically rather thinly scattered, but usually easy to see at any freshwater or coastal sites where medium-sized fish are plentiful. Size of bill and stature overall make this species unmistakable.

Range Rocky Mountains, Plains, New England, Great Lakes, Florida, Mid-Atlantic, Texas, California, Southeast, Northwest, Southwest, Eastern Canada, Western Canada, Alaska

Voice Utters a harsh, slightly menacing kraa-aar call.

Discussion A giant among terns, and the largest of its kind in the world. Most distinctive and diagnostic feature is huge, daggerlike bill that is dark red with dark subterminal band and small pale tip. Body is plump and robust, with gull-like proportions. Tail is forked, but outer feathers are not particularly long. Flight is powerful, direct, and gull-like. Plunge-dives after fish. Sexes are similar.