What is "ring-necked duck"

Ring-necked \Ring"-necked`\, a. (Zo["o]l.) Having a well defined ring of color around the neck.

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.

The ring-necked duck (Aythya collaris) is a diving duck from North America commonly found in freshwater ponds and lakes. The scientific name is derived from Greek '' aithuia'' an unidentified seabird mentioned by authors including Hesychius and Aristotle, and Latin collaris, "of the neck" from collum, "neck".