Summer Locations of Lesser Black-Backed Gulls (Larus fuscus) Wintering in Pennsylvania

Biological information related to migratory connectivity is still lacking for many bird species in North America. For widely distributed species, filling critical knowledge gaps throughout their annual cycle improves our understanding of local drivers influencing disparate growth of different populations and related conservation challenges. Such is the case for Lesser Black-backed Gulls (Larus fuscus graellsii) that established a growing wintering population in eastern North America in the 1970s. From 2018 to 2020, 11 wintering adult Lesser Black-backed Gulls were tagged with solar Argos telemetry in Pennsylvania and tracked through the annual cycle. Ten of those reached a summer destination during at least one of the three years, of which eight went to the southwest coast of Greenland and two spent at least part of the summer on Baffin Island, Canada. Nine tagged birds provided data for at least one full annual cycle, including summer ranges and migration routes. Our study is the first to track Lesser Black-backed Gulls wintering in North America throughout their full annual cycle and to connect the well-established Greenland breeding populations to the increasing winter populations in the eastern US.