Habitat use and population status of Yellow-billed and Pacific loons in western Alaska, USA

Abstract

ABSTRACT Effective conservation of sympatric avian populations depends on unbiased estimates of population size, distribution, and habitat use. For populations of Yellow-billed Loons (Gavia adamsii) and Pacific Loons (G. pacifica) co-occurring in Arctic wetland communities in Alaska, USA, such data are limited and difficult to obtain, hindering population assessments and decision making. The Yellow-billed Loon is also under consideration for additional protections under the Endangered Species Act due to small global population size, specific habitat requirements, and low fecundity, further increasing the need for information at the landscape scale. To help evaluate the population status and habitat use of both species, we used repeated aerial surveys and a dynamic multistate occupancy modeling approach to jointly estimate 1) probability of lake use and 2) probability of use for nesting for Yellow-billed and Pacific loon populations at the landscape scale on the Seward Peninsula and Cape Krusenstern, Alask...