This New Zealand endemic duck has white-headed females and black-headed males. Pairs are often seen together.
Females have white heads and males have black heads, making the sexes easy to tell apart. The bird is about 63 cm long; males weigh about 1.7 kg and females about 1.4 kg.
Pairs often stay together for life and feed and fly together. They eat grass, clover, seeds, and grain, and also feed on aquatic plants in wetlands. Nests may be on the ground or high in trees.
An extinction-risk assessment has not been added yet.