Northern Prairie Wildlife Research Center
STATUS: Locally common.
HABITAT: Inhabits lakes, ponds, and marshes from forested tundra to richly vegetated low tundra. During the breeding season, drakes rest along shorelines or on shoals, while in late fall and winter, both sexes form large rafts in open water, even in the open ocean well beyond the breakers. Winters on brackish and saltwater bays and estuaries, less commonly on large inland waters.
SPECIAL HABITAT REQUIREMENTS: Scattered wetlands in forested to open tundra.
NEST: Nests on the ground in a slightly elevated spot, in grasses on the tundra, usually near the shores of lakes or ponds, but up to 3,000 feet from water. Sometimes nests on islands, in marshes, or above or in water among rushes or wild rice.
FOOD: An expert diver; dives to depths of at least 20 feet, remaining underwater seeking food for up to a minute. A saltwater bird most of the year; prefers to feed in shoals with water less than 20 feet deep or in shellfish beds, also in freshwater lakes and ponds. Consumes a diet that is about half vegetative and half animal, including snails, aquatic insects, tadpoles, small fishes, and seeds in summer. During winter, also eats mollusks, crabs, barnacles, and other crustaceans. Also feeds on muskgrass, sea lettuce, eelgrass, wild celery, and widgeon grass.
REFERENCES: Cottam 1939, Johnsgard 1975b, Palmer 1976b, Terres 1980, Vickery in Farrand 1983a.