scaup

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Either of two diving ducks (Aythya marila or A. affinis) having predominantly black and white plumage in the male. Also called bluebill.

Century Dictionary and Cyclopedia

1. n. A Scotch form of scalp.
2. n. A duck, Fuligula or Fulix marila and related species. The common scaup inhabits Europe, Asia, and North America. It is from 18 to 20 inches long, and from 30 to 35 in extent of wings; in the male the head, neck, breast, rump, and vent are black; the back and belly are white, the former finely vermiculated with zigzag lines of black; the wing has a white speculum, and is lined with white; the bill is dull-blue, with black nail; the feet are dark-plumbeous; the iris is yellow. In the female a belt of white encircles the bill. A smaller species is F. affinis of North America. The ring-neck scaup, F. collaris or rufitorques, has a chestnut or orange-brown ring around the neck. All the scaups are near the pochards and redheads (including the canvasback) in general pattern of coloration, but the males have black instead of reddish heads. The American scaups, of 3 species, have many names, mostly local, as broadbill and bluebill (both with various qualifying words prefixed), blackhead and blackneck (with qualifying words), raft-duck, mussel-duck, greenhead, grayback, flock-duck, flocking-fowl, troop-fowl, shuffler, etc.

Wiktionary

1. n. Any of three species of small diving duck in the genus Aythya.
2. n. Scotland Alternative form of scalp; a bed or stratum of shellfish.

GNU Webster's 1913

1. n. Scot. A bed or stratum of shellfish; scalp.
2. n. (Zoöl.) A scaup duck. See below.

WordNet 3.0

1. n. diving ducks of North America having a bluish-grey bill