NATURAL HISTORY

YELLOW-BILLED LOON } Gavia adamsii
FAMILY: Gaviidae

DESCRIPTION: The yellow-billed loon shares the distinctive plumage of the common loon with its glossy black head, a “necklace” of white stripes, and white spotting on the back. But this species is set apart by its distinctive yellow bill. With a leg and pelvis structure adapted for swimming and diving, yellow-billed loons are quite clumsy on land, placing their nests at water’s edge and taking flight from the water.

HABITAT: Yellow-billed loons nest during the summer, preferring tundra lakes and ponds. Wintering grounds are generally near shore, but loons may also be found on large inland lakes.

RANGE: Yellow-billed loons’ summer breeding grounds include the subarctic and arctic tundra of northern Alaska, Canada, and Eurasia. Small numbers have been reported in Finland and Norway. Wintering occurs along the coast from British Columbia to Baja California. Several reliable inland sightings exist for migrating and wintering loons in western North America. Eurasian populations winter primarily around Scandinavia and along the Pacific coast of Siberia.

MIGRATION: Loons migrate between their breeding range in the arctic tundra and non-breeding areas farther south and east. Arrival along the Alaska coast and in Canada is usually from May to early June. Fall departure, which is closely associated with fledging of offspring, generally occurs from late August to mid-October.

BREEDING: Monogamous pairs will maintain the same territory each year, and nests are often reused. Two eggs are laid in June or July, and incubation lasts four weeks. Chicks are active within hours of hatching, yet they require an additional five weeks of care. Both parents share responsibility in raising the young.

LIFE CYCLE: Loons live an estimated 20 to 30 years. Reproductive maturity is reached at or after four years.

FEEDING: Yellow-billed loons feed primarily on fish, including sculpins, nine-spine sticklebacks, least cisco, and Alaska blackfish. They are visual, deep-water hunters, often submersing their bills and eyes while afloat to search for prey. Chicks are fed small, minnow-sized fish.

THREATS: Threats include oil and gas development, oil spills and other contaminants, reduction of prey base from overfishing, predation of eggs and chicks, hunting, and incidental bycatch. Throughout their range, these loons are also threatened by changing ocean conditions in the face of global warming and rising sea levels.

POPULATION TREND: An estimated 8,000 yellow-billed loons reside in Canada, and an additional 5,000 individuals are thought to occur in Russia. The breeding grounds of Alaska’s approximately 4,000 individuals were recently opened to oil and gas development by the Bush administration.