The Blue-billed Duck is a compact diving duck with males having a large scooped bright, light blue bill. Males have a rich deep chestnut plumage overall except the dark head and upper neck and an orange-brown to white area at the centre of the belly. The tail is dark with stiff pointed feather tips and is usually held flat on the surface of the water except when in display. The female has a brown bill with darker plumage than the male and each feather is barred with narrow bands of light brown. The upper tail is black and the chin and throat are speckled black.