Large, colorful duck, endemic to New Zealand. Sexes told apart by head color; male has a black head with slight green iridescence, female has a white head and upper neck. Note the large white wing patch on the outer wing of both sexes in flight. Widely distributed throughout New Zealand. Utilizes rivers, wetlands, and lakes, as well as open grassy areas and farmland. Noisy; males give loud honking alarm calls, while females are higher-pitched. Found in pairs or in large flocks, especially post-breeding. Distinguishable from vagrant Australian Shelducks by absence of white neck ring, chestnut or buff breast, and black undertail.