STATUS: Locally common throughout breeding range.
HABITAT: Found primarily on lakes, also rivers, estuaries, and shallow coastal bays and inlets. Loafs on beaches, sandbars, and driftwood.
SPECIAL HABITAT REQUIREMENTS: In freshwater habitat, islands isolated from mammalian predators.
NEST: Nests on the ground in colonies of a few to several hundred pairs on small, relatively flat islands, without tall (over 3 feet) obstructions, with loose earth suitable for heaping into nest mounds. Rarely, nests on floating islands of marsh plants. Colonies prefer open areas of annual grasses and forbs, shrubs, and nonvegetated areas.
FOOD: Primarily consumes fish caught by scooping pouch into water while swimming. Groups often cooperate in fishing. Adults require about four pounds of food daily, and feeding areas may be located far from nesting areas. Also feeds on some salamanders and crayfish.
REFERENCES: Knopf 1979, Knopf and Kennedy 1981, Lingle and Sloan 1980, Palmer 1962, Terres 1980.