Gavia adamsii

Birders in northern Utah were treated to an accidental vagrant during the current spring migration at Jordanelle Reservoir. The common loon is usually seen in Utah's larger reservoirs during spring migration. Marci Welch spotted this rare bird and was able to take some pictures.

The yellow-billed loon is the largest of the world's loons. It feeds primarily on fish, invertebrates, and some aquatic vegetation. When foraging, the yellow-billed loon dives to depths of more than 200 feet.

Yellow-billed loons prefer deep, clear water lakes for breeding. They are monogamous and will aggressively defend territory from other loons and diving ducks. Nests are reused. Both parents actively feed and tend young. Glaucous gulls, common ravens, jaegers, and Arctic foxes regularly prey upon young and eggs.

Yellow-bills are occasionally caught and drown in commercial nets. Oil spills pose a major threat.

Many birders would pass the yellow-billed loon off as a common loon. On closer inspection one can see the larger yellow bill. Otherwise it appears much like the common loon. The bill is longer, larger and is angled upward. The upper body is a pattern of black with white spots. Its underbody is white.

Like other loons, its vocalization includes the mournful wails, tremolos and yodels. The cadence is slower and in a lower pitch from the common loon. Audubon has the yellow-billed loon listed as a Conservation Watch List species.

There is not much information on the population size or trends. Estimates of the North American population are under 4,000. It is an Arctic species and occurs in Eurasia, as well as North America. It always breeds north of the tree line. Its winter range is the Pacific Ocean off southern Alaska and British Columbia.

Yellow-billed loons are not common anywhere they occur; it is indeed a rare occasion to have one appear in Utah.

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* BILL FENIMORE is owner of the Layton Wild Bird Center (www.wildbird.com/layton).