New Zealand Scaup

This is a small, entirely dark scaup. Male and female can easily be distinguished in the wild. The male's back, neck and head are black while the flanks are dark brown, the golden yellow eye is clearly visible and the bluish beak is ended by a black nail. The same beak can be found on the female, but she differs from the male in the absence of black (the full body is dark brown), the brown eye and the presence of white vertical bars at the base of the beak (present in half of the females). Juveniles look like the females but lack the white marks at the base of the beak.
In flight, the underside is very light and the upper wing very contrasting; the dark coverts oppose the white remiges (only their tips are dark, creating a dark trailing edge). Note that, contrary to what is seen in the Australian scaup, Aythya australis (the only species that can be confused in New Zealand), the large white wing bar does not reach the body.