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Ecology of Yellow-billed, Pacific, and Red-throated Loons on the North Slope of Alaska
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Three loon species breed in northern Alaska where oil development has expanded since the mid-1990s, and both yellow-billed and red-throated loons are species of conservation concern. USGS scientists are investigating niche overlap among the species and identifying factors that affect nesting and brood-rearing success using seven years of field data from the Colville River Delta. Aerial surveys throughout northern Alaska were used to quantify yellow-billed loon habitat preferences and estimate population size and trend. Yellow-billed loons preferred large, deep lakes, lakes with aquatic vegetation, and complex shorelines, and lakes near streams. These characteristics likely indicate fish availability, which is critical to successful reproduction. Average population size was < 3500 individuals, and there was no long-term trend in abundance (1986-2003). Fewer than 1000 nesting pairs probably inhabit northern Alaska in most years, mostly between the Meade and Ikpikpuk Rivers. The U.S Fish and Wildlife Service considered this information in finding that yellow-billed loons were warranted for listing (but precluded due to higher priorities) under the Endangered Species Act.
Earnst, S.L., Platte, R., Bond, L., 2006, A landscape-scale model of yellow-billed loon (Gavia adamsii) habitat preferences in northern Alaska: Hydrobiologia, v. 567, p. 227-236. [Highlight] [FullText] Catalog No: 1652 Earnst, S.L., Stehn, R.A., Platte, R., Larned, W.W., Mallek, E.J., 2005, Population size and trend of Yellow-billed Loons in northern Alaska: The Condor, v. 107, p. 289-304. [Highlight] [Abs] [FullText] Catalog No: 1364 Earnst, S.L., 2004, Status assessment and conservation plan for the yellow-billed loon ( Gavia adamsii): U.S. Geological Survey Scientific Investigations Report 2004-5258, p. 42. [Highlight] [FullText] Catalog No: 1288 Earnst, S.L., 2000, The Alaska Loon Working Group Project Directory- A description of current loon and grebe monitoring, research, and education projects: USGS, Forest and Rangeland Ecosystem Science Center, p. 67. [FullText] Catalog No: 1515
Earnst, Susan L. - Research Wildlife Biologist
Phone: 208-426-5209
Email: susan_earnst@usgs.gov
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