Lesser scaup by similar-looking "Aythya" hybrids. Except for hybrids between the two scaup species, the most reliable mark is the black bill-tip of hybrids, whereas in the scaups only the very point ("nail") of the bill is black. This is even recognizable at considerable range, as the scaups' bills appear uniformly grey from a distance, whereas those of hybrids look two-colored. European hybrids typically involve the tufted duck ("A. fuligula"), yielding offspring that have a small nape crest unlike any European "Aythya" species. Female and immature hybrids typically lack the white bill base, except in those between lesser scaup and ring-necked duck,
Greater scaup Atlantic coasts of North America, the coasts of northwest Europe, the Caspian Sea, the Black Sea, the coast of Japan, Yellow Sea and East China Sea. During the winter months, they are found in coastal bays, estuaries, and sometimes inland lakes, such as the lakes of Central Europe and the Great Lakes. In Europe, the greater scaup breeds in Iceland, the northern coasts of the Scandinavian peninsula, including much of the northern parts of the Baltic Sea, the higher mountains of Scandinavia and the areas close to the Arctic Sea in Russia. These birds spend the winters in the British