A distinctive large swan with black plumage and a bright red bill. On the water it appears almost completely black, while in flight the wings reveal broad white flight feathers. Young birds are similar in shape but appear dark grey rather than black. In Australia it can be told from Magpie Goose, which has a white belly and mostly white underwings with dark tips. This species frequents inland waters, rivers, treatment ponds, and coastal lagoons, and may gather in very large flocks on extensive wetlands.