Figure 27. California’s third Arctic Loon, photographed on 14 May 1995, was a first-spring bird at Bodega Bay, Sonoma County. Relative to the Pacific Loon, note this bird’s obvious white flank, large bill, somewhat flattened head, unmarked white throat, and whitish auricular (1995-057; Scott B. Terrill).

ARCTIC LOON Gavia arctica (Linnaeus, 1758)

Accepted: 4 (44%)	Treated in Appendix H: yes
Not accepted: 5	CBRC review: all records
Not submitted/reviewed: 3	Color image: none

Despite some probable hybridization (Storer 1978), the Arctic and Pacific Loons have been recognized as distinct species (AOU 1985). The Arctic Loon’s widespread subspecies arctica breeds across northern Eurasia and winters primarily along the Atlantic coast of Europe, but also in the Mediterranean, Black, and Caspian Seas; it is unconfirmed as a vagrant to the New World. Subspecies viridigularis breeds in northeastern Siberia and very locally in western Alaska, and winters along the Asian coast from Siberia south to Japan and eastern China. Migrants are encountered regularly at St. Lawrence Island and less so in the Aleutian Islands. The species is a casual or accidental vagrant elsewhere in the West with most records falling between 2 November and 18 June. These include a handful from Washington, one of them inland; two from Oregon (NAB 58:131); two from Colorado, one of them an early fall migrant in alternate plumage on 28 September 2005 (NAB 57:89, 141; 60:105); and one from the central Pacific coast of Baja California. Two older specimens from British Columbia reported as Arctic Loons (Godfrey 1986) proved to be Pacific Loons (Campbell et al. 1990a), and some recent reports from this province remain unconfirmed.

California’s first Arctic Loon was a widely seen bird in its first fall present from 2 to 17 November 1993 at Abbotts Lagoon in Marin County. Reinking and Howell (1993) published complete details of this record, along with a photograph of the bird; they also discussed the species’ taxonomy, field identification, and status in North America. Each of the state’s records is from the central coast, two in fall/winter (2 November–14 December) and two in spring (5 May–18 June). Appendix H reports on a more recent specimen record from Orange County.

Papers by McCaskie et al. (1990) and Dunn and Rose (1992) provide information on field identification of alternate-plumaged Arctic Loons; other plumages are covered by Walsh (1988), Roberson (1989), Schulenberg (1989), and Birch and Lee (1997).