Yellow-billed Loon

The yellow-billed loon (Gavia adamsii), also known as the white-billed diver, is the largest member of the loon or diver family. Breeding adults have a black head, white underparts and a chequered black-and-white mantle. Non-breeding plumage is drabber with the chin and foreneck white. Its main distinguishing feature is the long straw-yellow bill, which, because the culmen is straight, appears slightly uptilted. It breeds in the Arctic and winters mainly at sea along the coasts of the northern Pacific Ocean and northwestern Norway; it also sometimes overwinters on large inland lakes. It occasionally strays well south of its normal wintering range and has been recorded as a vagrant in more than 22 countries. This species, like all divers, is a specialist fish-eater, catching its prey underwater. Its call is an eerie wailing, lower-pitched than the common loon. == Taxonomy and etymology == First described by English zoologist George Robert Gray in 1859 based on a specimen collected in Alaska, the yellow-billed loon is a monotypic species, with no subspecies despite its large Holarctic range. It is closely related to the common loon, which it strongly resembles in plumage and behaviour; some taxonomists consider the two species to be allopatric forms…