Northern Prairie Wildlife Research Center
HABITAT: Inhabits shallow, dense bogs, swamps, and marshes, especially those with sweetgale or leatherleaf cover, from 1 to 2,000 acres in size, typically having a pH range of 5.5 to 6.8, and preferably near or in woodlands. It also uses small potholes, sloughs, and beaver flowages near larger wooded lakes or rivers with submerged and emergent vegetation. Winters on fresh or brackish marshes, lakes, and estuaries, rarely on strictly saline waters.
SPECIAL HABITAT REQUIREMENTS: Wetlands with an expanse of open water.
NEST: Nests on floating mats of vegetation, among hummocks, in clumps of marsh vegetation or on islands, on relatively dry sites usually within a few feet of water; seldom in emergent vegetation over water.
FOOD: Prefers to feed in shallow water, usually less than 6 feet deep. Consumes a diet that is 80 percent vegetative, consisting mostly of a few plant groups; seeds, bulbs, and succulent parts of waterlilies, pondweeds, sedges, grasses, and smartweeds. Also consumes some aquatic insects and mollusks.
REFERENCES: Bellrose 1976, DeGraff et al. 1980, Johnsgard 1975b, Mendall 1958, Palmer 1976b.