Gavia arctica
TAXONOMY
Colymbus arcticus Linnaeus, 1758, Sweden. Two subspecies recognized.
OTHER COMMON NAMES
English: Black-throated diver; French: Plongeon Arctique; German: Prachttaucher; Spanish; Colimbo Arctico.
PHYSICAL CHARACTERISTICS
23.6–29.6 in (60–75 cm); 5.7 lb (2.6 kg). Very similar to the smaller Pacific loon. Black upperparts with white patches, white underparts, black throat, and gray head and neck (darker near bill). Differentiated from the Pacific loon by white flanks, darker nape, more distinct white stripes on neck. In hand, throat shows faint greenish iridescence. Basic, juvenal, and second alternate plumages similar, with gray upperparts, crown, and nape and white underparts.
DISTRIBUTION
Breeds from extreme western Alaska across northern Eurasia to northern Scotland. Winters coastally from Japan to China and Europe.
HABITAT
Breeds on medium-to-large lakes and ponds in northern forests and tundra; winters on coasts.
BEHAVIOR
Similar to the Pacific loon.
FEEDING ECOLOGY AND DIET
Consumes a wide variety of fish, similar to other loons. Has been observed catching frogs.
REPRODUCTIVE BIOLOGY
Incubation 28–29 days, flight 60 days. In Scotland, artificial breeding platforms have been used to increase chick production by an estimated 44%.
CONSERVATION STATUS
Most populations stable, not listed on IUCN Red List of Threatened Birds.
SIGNIFICANCE TO HUMANS
A species of interest for many people. Nest platform programs have been started in Scotland, where populations have declined.
