'ring-necked blackhead' definitions:

Definition of 'ring-necked blackhead'

From: GCIDE
  • Ring-necked \Ring"-necked`\, a. (Zool.) Having a well defined ring of color around the neck. [1913 Webster]
  • Ring-necked duck (Zool.), an American scaup duck ({Aythya collaris}). The head, neck, and breast of the adult male are black, and a narrow, but conspicuous, red ring encircles the neck. This ring is absent in the female. Called also ring-neck, ring-necked blackhead, ringbill, tufted duck, and black jack. [1913 Webster]