Understanding population dynamics of migratory birds requires baseline knowledge of nonbreeding distributions, migratory routes, and population-specific migratory connectivity. The Canada Warbler (Cardellina canadensis) is a declining Nearctic–Neotropical migratory songbird, but limited information exists describing its population-specific migration ecology. We aimed to understand how individuals from a central Appalachian breeding population were spatially distributed during the stationary nonbreeding period, infer the strength and pattern of migratory connectivity, and understand migratory route patterns. We deployed 32 geolocator tags on adult male birds in 2020 and 10 tags retrieved in 2021 provided usable data. Stationary nonbreeding season locations suggest moderate population connectivity, with birds clustered on the Andean slopes on each side of the Magdalena Valley in northern Colombia. Post-breeding (boreal fall) migration was largely overland through Mexico and Central America, and pre-breeding (boreal spring) migration routes were significantly farther east based on the westernmost longitude recorded during migration (mean difference = 232 km), consistent with a pattern of counterclockwise loop migration. The evidence of counterclockwise loop migration is a novel finding in Canada Warblers and suggests the shorter duration of pre-breeding migration may be due to a time-minimizing strategy involving trans-Gulf flights. Our data additionally provide the first insight into the migratory ecology of a population of Canada Warblers breeding near the southern extent of their range and serve as a foundation for full annual cycle demographic modeling.

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