A rather small, compact diving duck with a rather large head, a long, heavy bill, and a fairly long tail.
Larger than a Harlequin Duck, smaller than a Common Eider.crow-sized
Despite differences in color, both sexes have blocky head with flat crown and thick gray bill.
Mostly white head with large black eye, black collar around neck, and creamy-buff belly with black spot on side.
Males have a mostly white head, black back, and creamy-buff belly. Females are dark brown with a pale eyering and a heavy gray bill.
Breeds in shallow tundra wetlands. Male has mostly white head with large black eye. Black back shows white stripes at rest; black rear.
Male in flight has extensively white forewing. Female has blue-black secondaries bordered in white and white underwings.