Northern Prairie Wildlife Research Center
STATUS: Fairly common; more abundant west of the Mississippi River.
HABITAT: Prefers shallow prairie marshes, particularly those with abundant plant and animal life floating on the surface, but also occupies potholes, sloughs, and marshes in taiga, forests, and (less commonly) cultivated country. It tolerates a wide range of water conditions, from clean and clear to muddy; flowing to stagnant; considerably alkaline, and even heavily polluted. Likes to have mudbanks or low sloping shorelines with short or flattened vegetation for loafing. Winters in freshwater and brackish habitats.
SPECIAL HABITAT REQUIREMENTS: Shallow waters with muddy bottoms, surrounded by dry grassy areas for nesting.
NEST: Nests on dry ground in a slight hollow, preferably in short grasses within 300 feet of water, but will nest in hayfields, meadows, and rarely bulrushes if grasses are not available. Seldom nests in weed patches, and avoids woody vegetation such as willows.
FOOD: A filter feeder; prefers to feed in shallow waters, but will actively feed in deep waters containing submergent and surface vegetation. Consumes a considerable amount of microscopic animal life such as ostracods, copepods, and similar crustaceans, and macroscopic animal life as well. Eats fingernail clams, mollusks, and insects for one quarter of the diet. Also eats grasses, sedges, water lilies, pondweeds, bulrush seeds, algae, and smartweeds.
REFERENCES: Bellrose 1976, DeGraff et al. 1980, Johnsgard 1975b, Palmer 1976a, Poston 1974.