Family: Gaviidae, Loons view all from this family

Description 23-28" (58-73 cm). W. 43-51" (110-130 cm). Highly similar to Pacific Loon; until recently, the two were considered a single species. The Arctic is slightly larger and longer-necked; has a white flank patch before the tail, visible at the waterline and in flight. Striped patch on side of neck in breeding plumage is more conspicuous than the Pacific's (frequently visible at some distance and in flight); nape and hindneck darker. The Siberian race of Arctic (G. a. viridugularis), which breeds in Alaska, typically has a green iridescent throat patch (visible only at close range), whereas the throat patches of the Pacific and of the European race of Arctic Loon (G. a. arctica) are typically iridescent purple.

Habitat Tundra and taiga lakes and marshy inlets; coastal areas and open ocean in winter.

Nesting 1-3 brownish eggs with scattered markings, laid on mass of mud and aquatic vegetation at edge of shallow water.

Range Primarily an Old World species, breeds in North America only at isolated sites in western Alaska; possible along either coast in winter.

Voice Similar to Pacific Loon, a harsh kok-kok-kok-kok. Adults on nesting ground issue an eerie, long-carrying moan or wail.

Discussion Since the Arctic and Pacific Loons were split in 1985, field observers have sought reliable means of separating the two species, especially in winter plumage. Despite gains in this regard, the challenge of identifying winter Arctics remains formidable. Vagrants might appear on either coast, though no accepted records presently exist for the Atlantic. Like its North American counterpart, the Arctic Loon feeds on fish, mollusks, crustaceans, and some amphibians and aquatic vegetation.