Striking and substantial, the White-winged Duck is a tropical forest species from South East Asia. Historically widely distributed, loss and disturbance of its habitats has resulted in small and fragmented populations which are susceptible to hunting: it is listed as Endangered. White-winged Ducks are also among the least known waterfowl, as in the wild they are shy, wary and largely nocturnal.
In appearance it bears a strong resemblance to the Muscovy Duck, and it was previously placed in the same genus, Cairina. However, DNA evidence suggests that it is more closely related to the diving ducks, so it is now in a genus of its own, Asarcornis. The sexes are similar, having freckled white heads and necks with dark bodies, contrasting with striking white forewings. Females are smaller, with heavier freckling on their heads.
These ducks have always been rare in collections, but they have been bred regularly at WWT Slimbridge since the early 1970s. Today a number of collections have pairs, while a studbook is maintained to coordinate breeding. The biggest challenge with the captive flock is inbreeding, as they are descended from just seven birds. They can be aggressive in captivity.