Gavia immer
(Common Loon)

Physical Description:
Size: 28-36" (70-90 cm). A large, long-bodied, low-swimming waterfowl. Bill stout, straight, dagger shaped, dark. Breeding adults have a glossy- green/black head. Back black, checkered with white. White necklace. In winter, gray- brown above and white below.

Similar Species- Yellow-billed loon has an upturned, yellow bill. Pacific loon is smaller with pale gray crown and nape

Song:
Calls are a series of yodels and falsetto, maniacal laughter. A tremulous ha-oo- oo-oo. Usually silent in winter.

Distribution:
Breeds in Iceland, Greenland, and across Canada and northern U.S. to Alaska. Winters along Pacific Coast from Aleutians to northern Mexico, and along Atlantic and Gulf coasts from Newfoundland to Florida and Texas.

Habitat:
Primarily marine when not breeding. During migration, found on inland lakes, rivers, and coastal waters. In Idaho, breeds occasionally on a few lakes and reservoirs in southeastern Idaho, mostly in Fremont County.

Diet:
Feeds mainly on fishes, but may also eat amphibians and various invertebrates.

Ecology:
Builds platform nest on ground, at edge of shallow water. If nesting on small lake, may use adjacent lake for supplementary foraging. Dives from water surface to obtain food. Studies in different sections of U.S. indicate range of territory size from 39 ha (Saskatchewan) to 503 ha (New Hampshire). Species occurs as transient and breeder in Idaho, occupying water bodies that have suitable conformation and are not affected by human disturbance factors. Size and elevation of lake, water depth and clarity, and nesting habitat requirements are important factors in site use.

Reproduction:
Both sexes incubate usually 2 eggs (but frequently 1), for 26-31 days. Initially, both sexes tend young, which fly at 10-12 wk. Most brood mortality may occur within a week of hatching. Generally, loss of eggs to predators is not primary cause of breeding failure. Female renests usually 5-14 days after egg loss. Sensitive to disturbance by boaters at the nest.

Conservation:

Element Code:	ABNBA01030
Status:	Protected nongame species
Global Rank:	G5
State Rank:	S1
National Rank:	N4B,N5N

Important State References:
Fitch, T. and C.H. Trost. 1985. Nesting status of the common loon in Idaho. Dept. Biol. Sciences, Idaho St. Univ., Pocatello. 23pp.