STATUS: Large breeding colonies and winter flocks common.
HABITAT: Inhabits marshy lakes and ponds, and large pools in streams or rivers in the prairie region of North America. Less typically inhabits marshes with some open water. During winter, found on salt lakes, bays, estuaries, and seacoasts.
SPECIAL HABITAT REQUIREMENTS: Freshwater lakes and ponds larger than 18 acres, with shallow margins and emergent vegetation.
NEST: Nests in compact colonies or sometimes singly, in sheltered areas, or in shallow water away from emergent vegetation. Builds a floating nest that is a platform of marsh vegetation built up from the bottom or anchored to reeds.
FOOD: Gleans land insects from surface of water, or captures aquatic insects during dives. Also takes small crustaceans, small fishes, leech eggs, mollusks, and amphibians.
REFERENCES: Faaborg 1976, Grinnell and Miller 1944, Low and Mansell 1983, Palmer 1962, Ratti in Farrand 1983a, Terres 1980, Verner and Boss 1980, Wetmore 1924.