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,
What Bird is That? of "What Bird is That?" It was published in 1984 and incorporated all of Cayley’s paintings created over many years for his vision of releasing a “big bird book” and included a revised taxonomy. In the 53 years since its first edition, more than a hundred new bird species had been identified in Australia. Scientific names had been changed and groups of birds had been reordered. Lindsey brought "What Bird is That?" up-to-date with the latest birding conventions of the time, as well as contributing a valuable supplementary list of birds and a scholarly catalogue of Cayley’s paintings. The "Signature