Northern Prairie Wildlife Research Center
STATUS: Common; population declining in the eastern United States.
HABITAT: Inhabits freshwater marshes, sloughs, ponds, and shallow lakes bordered by hardstem bulrush, cattails, reeds, or sedges in prairies and intermountain parks. Winters primarily on freshwater and brackish lakes, rivers, and estuaries, in areas well protected from heavy wave action.
SPECIAL HABITAT REQUIREMENTS: Wetlands at least 1/2 acre in size bordered by permanent, dense emergent vegetation, with stable water levels during the nesting season.
NEST: Usually nests in emergent vegetation or on a floating mat of dead plant material over shallow water 6 to 14 inches deep, fairly close to shore, but occasionally on dry ground or over water 4 feet deep. Tends to be semi-parasitic, sometimes laying eggs in nests of other waterfowl, especially the canvasback; also incubates own nests. Prefers to rear broods in potholes at least 1 acre in size, with deeper waters than those used for nesting.
FOOD: Feeds in marshes, sloughs, and ponds more than other diving ducks, mainly in water less than 6 feet deep. Has a diet that is 90 percent vegetative, consisting primarily of seeds and vegetative parts of aquatic plants and including some insects and shellfish.
REFERENCES: Bellrose 1976, DeGraff et al. 1980, Johnsgard 1975b, Lokemoen 1966, Palmer 1976b, Tate and Tate 1982, Weller 1964.