The Yellow-billed Loon

Abstract

The Yellow-billed Loon, known in Europe as the White-billed Diver, is a relatively rare bird nesting in arctic tundra regions of North America and Eurasia. This species was first described by G. R. Gray in 1859 ( 1 ), and named ( Gavia adamsii ) after the surgeon Dr. Edward Adams (who collected the first specimen) aboard the H.M.S. Enterprise on a voyage through Bering Strait. The Yellow-billed Loon is closely related and similar in appearance to the Common Loon ( G. immer ), but distinguished from the latter by bill shape and color. Further, the Yellow-billed Loon breeds generally north of the range of its more widespread relative, although the 2 species overlap on marine wintering grounds in the Pacific Northwest. Increasingly, however, vagrant Yellow-billed Loons have been recorded wintering well inland in North America, a phenomenon that likely stems in part from improved information on field identification of loons in Basic plumage.