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
Greater scaup 100% of female greater scaup, and 77% of female lesser scaup, had escalated levels of selenium in their bodies. Selenium is an occurring semimetallic trace element that occurs naturally in some soils and minute amounts are necessary for animal life. However excessive selenium can cause reproductive harm and is highly toxic. On their migration across the Great Lakes, greater scaups are at risk of ingesting selenium by eating the invasive zebra mussels, which can render a hen infertile. This sterilization of hens is causing the population to decrease. In a study of 107 scaup, they all had traces of iron,