Size and Retention of Breeding Territories of Yellow-Billed Loons (Gavia adamsii) in Alaska and Canada

Abstract. Yellow-billed Loons (Gavia adamsii) breed in lakes in the treeless Arctic and are globally rare. Like their sister taxa, the well-documented Common Loon (G. immer) of the boreal forest, Yellow-billed Loons exhibit strong territorial behavior during the breeding season. Little is known about what size territories are required, however, or how readily territories are retained from year to year. An understanding of territory dynamics and size is needed by management agencies as most of the U.S. breeding population of Yellow-billed Loons resides in the National Petroleum Reserve-Alaska where oil and gas development is expected to increase in the next few decades. Using locational data from a set of Yellow-billed Loons marked with satellite transmitters, we quantified an index of territory radius for each of three breeding populations: two in Alaska and one in Canada. The mean territory radius was 0.42 km for Yellow-billed Loons summering on lakes within the Seward Peninsula in northwest Alaska, 0.69...