Lesser scaup that looks strongly curved or even angular due to the small crest. When the birds raise their heads, these differences are most easy to spot, and after observing the two species in direct comparison it usually becomes easy to recognize. In fact, in alternate plumage the lesser scaup drake may appear identical in shape and size to a drake of the ring-necked duck ("A. collaris"); the black back and wings of that species are hard to confuse with the light ones of the lesser scaup male though. Particularly in the case of vagrant birds in Europe, the identification is complicated
New Zealand scaup for twenty to thirty seconds and go down three metres to look for aquatic plants, small fish, water snails, mussels and insects. It is sometimes seen with the Australian coot ("Fulica atra"); it is thought that the scaup takes advantage of the food stirred up by the coots as they fossick for shrimps. It is found throughout both the North and South Islands of New Zealand in deep freshwater lakes and ponds. Unlike other members of this genus, the scaup is not migratory, although it does move to open water from high country lakes if they become frozen in winter.