Yellow-billed loon

Gavia adamsii

TAXONOMY

Colymbus adamsii Gray, 1859, Alaska. Monotypic.

OTHER COMMON NAMES

English: White-billed diver; French: Plongeon a Bec Blanc; German: Gelbschnabel-Eistaucher; Spanish: Colimbo de Adams.

PHYSICAL CHARACTERISTICS

30–36 in (76–91cm); 9.0–14.1 lb (4.1–6.4 kg). Largest loon, with the largest bill. Very similar to the common loon in all plumages. In alternate plumage, black upperparts, neck, and head; white striping on the neck and white checkering on the back. Underparts white. Juvenal, second alternate, and winter plumages similar, dark gray brown upperparts, head, and nape; white underparts and throat. Bill is large and upturned, yellow to ivory.

DISTRIBUTION

Replaces common loon in high arctic, breeds in Canada and Alaska, also across Siberia. Winters along coasts in northern Pacific, and along the coast of Norway. Winters farther north than other loons.

HABITAT

Breeds in large tundra lakes; winters along coasts.

BEHAVIOR

Similar to the common loon.

FEEDING ECOLOGY AND DIET

Up-turned bill has been suggested as an adaptation for feeding along water bottom; very little data on diet, probably similar to other loons.

REPRODUCTIVE BIOLOGY

Nests from June to September on hummocks near breeding ponds. Incubation around 28 days; young leave nest within one day of hatching. Young can fly at about 11 weeks. Predators include foxes (Aloplex), ravens (Corvus), and gulls (Larus).

CONSERVATION STATUS

Rarest of the loons, but not threatened. Populations stable.

SIGNIFICANCE TO HUMANS

Taken occasionally for subsistence by Inuit.