Source : Webster's Revised Unabridged Dictionary (1913)
2. (Zo["o]l.) A scaup duck. See below.
{Scaup duck} (Zo["o]l.), any one of several species of
northern ducks of the genus {Aythya}, or {Fuligula}. The
adult males are, in large part, black. The three North
American species are: the greater scaup duck ({Aythya
marila}, var. nearctica), called also {broadbill},
{bluebill}, {blackhead}, {flock duck}, {flocking fowl},
and {raft duck}; the lesser scaup duck ({A. affinis}),
called also {little bluebill}, {river broadbill}, and
{shuffler}; the tufted, or ring-necked, scaup duck ({A.
collaris}), called also {black jack}, {ringneck},
{ringbill}, {ringbill shuffler}, etc. See Illust.. of
{Ring-necked duck}, under {Ring-necked}. The common
European scaup, or mussel, duck ({A. marila}), closely
resembles the American variety.