There is considerable debate about the taxonomy of this species with some authorities considering it to be a sub-species of Ruddy Duck Oxyura jamaicensis which is found in North America and the Caribbean as well as in South America. Others treat the South American sub-species O. j. andina and O. j. ferruginea as a separate species.

The male is chestnut with a black head and a bright blue bill which has a slight bump over the nostril as can be seen in photo 2. This is one feature that distinguishes it from the Lake Duck others being the more rounded head and the steeper forehead. It usually holds its tail cocked.