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Revealing migratory path, important stopovers and non-breeding areas of a boreal songbird in steep decline

December 22, 2021

The Olive-sided Flycatcher (Contopus cooperi) is a steeply declining aerial insectivore with one of the longest migrations of any North American passerine. We deployed light-level geolocators and archival GPS tags on breeders in boreal Alaska to determine migratory routes, important stopovers and non-breeding locations. Data from 16 individuals revealed a median 23,555 km annual journey (range: 19,387, 27,292 km) over 95 days (range: 83, 139 days) with wintering occurring in three regions of South America (NW Colombia/Ecuador, central Peru and W Brazil/S Peru). We developed a new method to identify “Important Stopovers” by quantifying intensity of use (a function of bird numbers and stop durations) along migratory routes. We identified 13 Important Stopovers that accounted for ~66% of the annual migratory period, suggestive of refueling activities. Some sites coincided with key areas previously identified for other Neotropi- cal-Nearctic migrants. Percent land “protected” at Impor- tant Stopovers, as defined by IUCN, ranged from 3.8% to 49.3% (mean [95% CI]: 17.3% [9.6, 25.0]). Total migration speed did not differ by season (median: 255 km day-1, range: 182, 295km day-1), despite greater spring travel dis- tances. Birds with longer non-breeding periods, however, migrated north faster. Climate-driven mismatches in migratory timing may be less of a concern for western than for eastern flycatcher populations, given recent con- generic analyses (C. sordidulus, C. virens). However, accel- erated high-latitude changes, may nonetheless impact boreal breeders.

Citation Information

Publication Year 2021
Title Revealing migratory path, important stopovers and non-breeding areas of a boreal songbird in steep decline
DOI 10.1515/ami-2020-0116
Authors Julie C Hagelin, Michael T. Hallworth, Christopher P Barger, James A. Johnson, Kristin A DuBour, Grey W Pendelton, Lucas H. DeCicco, Laura A McDuffie, Steven M. Matsuoka, Marian A Snively, Peter P. Marra
Publication Type Article
Publication Subtype Journal Article
Series Title Animal Migration
Index ID 70227046
Record Source USGS Publications Warehouse
USGS Organization Alaska Science Center Biology WTEB

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