scaup

noun

1. any of several diving ducks of the genus Aythya, especially A. marila (greater scaup), of the Northern Hemisphere, having a bluish-gray bill.

noun

1. either of two diving ducks, Aythya marila (greater scaup) or A. affinis (lesser scaup), of Europe and America, having a black-and-white plumage in the maleAlso called (US): bluebill, broadbill