The recent Great Salt Lake Bird Festival ended on a high note when Tim Avery and a group of birders from Utah and Texas spotted a yellow-billed Loon at Rockport Reservoir. Avery was leading the Marathon Birding Day field trip, which seeks the maximum number of species in a single day (his group saw 128 species.) The highlight, though, was the yellow-billed loon, which was a life bird for all of the participants, including Avery.
Kris Van Fleet was able to capture this image, so the sighting can be documented by the Utah Ornithological Society's Rare Bird Committee. It was a life bird for Van Fleet too. Birding enthusiasts from all over northern Utah are "flocking" to Rockport to see this rare migrating loon.
The yellow-billed loon is the largest of the world's loons. It is an Arctic species and occurs in Eurasia, as well as North America. Its winter range is the Pacific Ocean off southern Alaska and British Columbia. Yellow-billed loons always breed north of the tree line and are not common anywhere they occur. A yellow-billed appearance in Utah is a rare occurrence.
Many birders would pass off the yellow-billed loon as a common loon, which is typically seen in Utah's larger reservoirs during spring migration. The biggest difference is the yellow bill, which is longer, larger and angles upward. The upper body is a pattern of black with white spots. Its underbody is white.
As with other loons, vocalization includes mournful wails, tremolos and yodels. The cadence is slower and in a lower pitch from the common loon.
The birds feed primarily on fish, invertebrates, and some aquatic vegetation. When foraging, they can dive to depths of more than 200 yards.
Yellow-billed loons prefer deep, clear water lakes for breeding. They are monogamous and will aggressively defend a 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 loon eggs and the young.
Audubon has the yellow-billed loon listed as a Conservation Watch List species. There is not much information on population size or trends; estimates of the North American population are under 4,000.
Yellow-bills are occasionally caught and drown in commercial nets. Oil spills pose a major threat.
Bill Fenimore is owner of the Layton Wild Bird Center (www.wildbird.com/layton) and author of Backyard Birds of Utah. Join Fenimore for a free bird walk to the Kaysville foothills on June 6, leaving at 8 a.m. from the Layton Wild Bird Center, address.