13-15 1/2" (33-39 cm). Black above and white below with a gray bill. White patch from behind eye to back of head; white wing patches visible in flight. Females brown above and gray below; whitish breast and elongated white patch on face.
Similar Species- Male Hooded Merganser, male goldeneyes, female Harlequin Duck
Hoarse, crow-like qua-qua.
Breeds from central Alaska and parts of western Canada, south to northern Washington, and east to northern Montana; also breeds (locally) south to mountains of Oregon and northern California. Winters from Alaska, Great Lakes, and Maritime Provinces, south to Mexico and Gulf Coast.
Found on lakes, ponds, rivers, and seacoasts. Winters on sheltered bays and estuaries. In Idaho, occupies ponds, lakes, rivers, and reservoirs; winters on larger bodies of open water.
In freshwater, feeds on aquatic insects, snails, amphipods, small fishes, and some aquatic plants. In saltwater, eats crustaceans, mollusks, fishes, and some aquatic plants.
Dives underwater to obtain food. Nests in tree near water, either in natural cavity or in cavity made by flicker or woodpecker. Will also nest in burrow in bank. Female strongly defends brood territory. British Columbia study found that breeding density was not limited by nest sites, but rather by territorial behavior. Usually seen in small groups (2-3 individuals). Usually migrates at night. Breeds uncommonly on mountain lakes in Idaho.
Breeding begins mid- May in southern range, to early June in north. clutch size varies from 6-11 eggs (usually 7-9). Incubation lasts 28-33 days; female incubates eggs and tends young, which fly 50-55 days after hatching and breed at 2 yr.
No references are available at this time.