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International migration patterns of Red-throated Loons (Gavia stellata) from four breeding populations in Alaska

January 10, 2018

Identifying post-breeding migration and wintering distributions of migratory birds is important for understanding factors that may drive population dynamics. Red-throated Loons (Gavia stellata) are widely distributed across Alaska and currently have varying population trends, including some populations with recent periods of decline. To investigate population differentiation and the location of migration pathways and wintering areas, which may inform population trend patterns, we used satellite transmitters (n = 32) to describe migration patterns of four geographically separate breeding populations of Red-throated Loons in Alaska. On average (± SD) Red-throated Loons underwent long (6,288 ± 1,825 km) fall and spring migrations predominantly along coastlines. The most northern population (Arctic Coastal Plain) migrated westward to East Asia and traveled approximately 2,000 km farther to wintering sites than the three more southerly populations (Seward Peninsula, Yukon-Kuskokwim Delta, and Copper River Delta) which migrated south along the Pacific coast of North America. These migration paths are consistent with the hypothesis that Red-throated Loons from the Arctic Coastal Plain are exposed to contaminants in East Asia. The three more southerly breeding populations demonstrated a chain migration pattern in which the more northerly breeding populations generally wintered in more northerly latitudes. Collectively, the migration paths observed in this study demonstrate that some geographically distinct breeding populations overlap in wintering distribution while others use highly different wintering areas. Red-throated Loon population trends in Alaska may therefore be driven by a wide range of effects throughout the annual cycle.

Publication Year 2018
Title International migration patterns of Red-throated Loons (Gavia stellata) from four breeding populations in Alaska
DOI 10.1371/journal.pone.0189954
Authors Sarah E. McCloskey, Brian D. Uher-Koch, Joel A. Schmutz, Thomas F. Fondell
Publication Type Article
Publication Subtype Journal Article
Series Title PLoS ONE
Index ID 70196290
Record Source USGS Publications Warehouse
USGS Organization Alaska Science Center Biology WTEB