Source : Webster's Revised Unabridged Dictionary (1913)

Bluebill \Blue"bill`\, n. (Zo["o]l.)
   A duck of the genus {Fuligula}. Two American species ({F.
   marila} and {F. affinis}) are common. See {Scaup duck}.

Source : WordNet®

bluebill
     n : diving ducks of North America having a bluish-gray bill
         [syn: {scaup}, {scaup duck}, {broadbill}]