New Zealand Scaup Black Teal "In flight" (Aythya novaeseelandiae)

Scaup is the most common of the small New Zealand ducks
The male and female can be easily distinguished by sight. The male is glossy black with an iridescent green sheen, bright yellow eye and has a high pitch whistle call. The female is grey-brown and quacks rather than whistles.
Occasionally they will dabble in mud and shallow water, but prefer deeper water where they can dive for their food. They can dive to a depth of 23 metres. They feed on aquatic plants and a range of invertebrates such as snails.
While the female is nesting the male stays close by. Indeed the occurrence of a solitary male floating near the shoreline during the breeding season is an almost sure indication of the presence of a nesting duck.