Northern Prairie Wildlife Research Center
HABITAT: Uses a wide variety of habitats, including sandy, rocky, or wooded islands, stabilized sand dunes, margins of tundra lakes, Spartina marshes, cliffs, grass meadows, and buildings. In winter, occurs primarily along the shore of the ocean or other bodies of water, concentrating on beaches and in areas where food is likely to be abundant.
SPECIAL HABITAT REQUIREMENTS: Nesting sites must be free of terrestrial predators and within 25 miles of a dependable source of food.
NEST: Usually nests in exposed sites on the ground in small to large colonies, but occasionally in trees. Prefers to nest in low sites; depending on habitat may nest at the base of boulders, stumps, or bushes on grassy slopes, near large, tall clumps of vegetation, on drift adjacent to salt marshes, or on rock or grassy substrates.
FOOD: Feeds opportunistically in garbage dumps, around seafood-processing operations, in pastures and cultivated fields, on lawns, tundra, and beaches, and at sea. Consumes largely animal matter, including small mammals, birds and bird eggs, amphibians, fishes, shellfishes, and a great variety of invertebrates, plus berries and some fruit, as well as carrion and, at times, garbage.
REFERENCES: Burger and Shisler 1978, Clapp et al. 1983, Cramp and Simmons 1983, Forbush and May 1955.