BRI researchers, in a long-term collaboration with the National Parks Service, have provided the first documentation of the migratory routes and wintering locations of two territorial adult male Arctic Warblers from Denali National Park and Preserve, Alaska. This study, carried out as part of the National Park Service’s Critical Connections Program and published in Ecology and Evolution, used geolocator data and Bayesian movement models to determine the most likely daily positions of these animals and estimate migratory routes and timings.
Data shows the warblers departing the breeding grounds in Denali by 8/29/18 and 9/3/16, flying northwest, leaving North America from the western edge of the Lisburne Peninsula. The warblers arrive at the wintering grounds by 10/20 and 10/15. The autumn migration route included overwater flights from Alaska to Russia and China and Japan into the Philippines and the surrounding Pacific Islands. This study provides previously unknown information on stopover and wintering locations for Arctic Warblers and indicates that this species may migrate further overwater than previously thought, as the individuals wintered in not only the Philippines but also on the island of Palau, suggesting that an additional study is needed to document their wintering range. Wintering on remote islands such as Palau requires longer overwater flights, increasing the mortality risk during migration due to encounters with extreme weather events.
This documentation is significant, as descriptions of broadscale migratory movements in songbirds species and migratory routes lack representation in the current state of the science. “Movements and connectivity across the full annual cycle can be a critical driver of speciation and further complicate conservation activities. Effective conservation efforts require knowledge of space and resource use during the breeding and non-breeding season and an understanding of migratory movement and connectivity.” As Arctic Warblers alter their breeding range and habitat preference, it is recommended that current efforts are expanded to understand Arctic Warbler population status and the ecological drivers of population trends across their annual cycle.
