ring-necked blackhead

from The Collaborative International Dictionary of English v.0.48

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]