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.