from
The Collaborative International Dictionary of English v.0.48
Scaup \Scaup\ (sk[add]p), n. [See {Scalp} a bed of oysters or
mussels.]
1. A bed or stratum of shellfish; scalp. [Scot.]
[1913 Webster]
2. (Zool.) A scaup duck. See below.
[1913 Webster]
{Scaup duck} (Zool.), 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 ({Aythya affinis}), called
also {little bluebill}, {river broadbill}, and {shuffler};
the tufted, or ring-necked, scaup duck ({Aythya
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 ({Aythya marila}), closely
resembles the American variety.
[1913 Webster]