Redhead (bird) blue bill during the breeding season. The redhead is in the family Anatidae (ducks, swans, geese) and genus "Aythya" (diving ducks). There are currently no described subspecies of the redhead. The redhead and the common pochard form a sister group which itself is sister to the canvasback. This group is then sister to the monophyletic group consisting of the white-eyes (hardhead, Madagascar pochard, and the sister species ferruginous duck and baer's pochard) and scaups (New Zealand scaup, ring-necked duck, tufted duck, greater scaup, lesser scaup). The redhead is a pochard, a diving duck specially adapted to foraging underwater. Their legs
Lesser scaup scientific name is derived from Ancient Greek "aithuia" an unidentified seabird mentioned by authors including Hesychius and Aristotle, and Latin, "affinis" "related to", from its resemblance to the greater scaup. Adults are long, on average. The species can weigh ; males weigh on average and weigh noticeably less, at on average. Wing lengths (not wingspans) are about in males and in females; the tarsus is about long, and the bill . The wingspan is . The adult males (drakes) in alternate plumage have a black, iridescent head and a small tuft at the hindcrown, a black breast, a whitish-grey back