C-pif-02. contributed papers biology of nearctic-neotropical migratory birds

Migratory connectivity is a measure of the strength of spatial connections between populations at different periods of the annual cycle, such as the breeding and overwintering periods of migratory birds. There is a general lack of studies focused on migratory connectivity for small songbirds of conservation concern, making conservation planning problematic. The challenge in determining migratory connectivity is in the identification of non-breeding and breeding areas for specific populations. Through the miniaturization of geolocators, it is now possible to track small songbirds of conservation concern year-round providing the data needed to determine migratory connectivity. The Canada Warbler (Cardellina canadensis) is a threatened Neotropical migrant. This species has declined by 2.3% per year from 1966 to 2012. The rate of decline is not consistent across its range; eastern population are declining more than western populations and southern populations are faring better than northern populations. The cause of overall population decline is unknown, as is the variation among the rates of decline across their range, but it is hypothesized to be linked to wintering ground factors. Most of the existing research on Canada Warblers is focused on breeding ground ecology. For the conservation of Canada Warblers to be successful, more information is required on wintering sites, as well as the potential drivers of the population decline. Our objective was to determine the migratory connectivity of the Canada Warbler to guide conservation priorities. We tracked individuals using geolocators from seven sites spatially stratified across the breeding range. Using these geolocator data, we quantified migratory connectivity of seven breeding populations by using Mantel tests, and determined whether these geographically distinct breeding populations overwinter in overlapping areas. Understanding migratory connectivity is critical, as it is invaluable tool in drafting conservation plans for at-risk species.