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
Greater scaup zinc, manganese, copper, lead, cadmium, cobalt and nickel in their tissue samples with varying concentrations of metals in different types of tissues. Further analysis revealed that the kidneys had the highest levels of cadmium, the liver had the highest levels of copper and manganese, the liver and the stomach had the highest levels of zinc, and the lungs and liver had the highest levels of iron. There was no difference in concentration when comparing genders. Greater scaup are rated as a species of least concern by the IUCN Redlist. During aerial population surveys greater and lesser scaup are counted together,