Abstract
BackgroundTo effectively conserve migratory species, the entire range encompassed by their annual life cycle needs to be considered. Most research on Nearctic-Neotropical migratory birds has focused on the breeding grounds resulting in a general lack of knowledge regarding the wintering and migratory periods. The Canada Warbler (Cardellina canadensis) has declined by 71% from 1970 to 2012, at a rate of 2.9% per year, and is listed as Threatened in Canada. As with most Nearctic-Neotropical migrants, conservation efforts outside the breeding range are limited by a poor understanding of migration routes and the connectivity between specific breeding and wintering populations.ResultsTo determine migratory routes of multiple breeding populations of Canada Warblers, we directly-tracked individuals using light-level geolocators deployed at four sites across the breeding range, spanning approximately 43 degrees in longitude (Alberta, Manitoba and Québec, Canada, and New Hampshire, USA). Twenty-five geolocators with usable data were recovered from three sites and were analyzed using FlightR to determine fall migration routes (n = 18) and individual wintering sites (n = 25). Individuals from all breeding populations took a western fall migration route at the Gulf of Mexico; with 77.8% of birds funnelling into a narrow geographic space along the western side of the Gulf of Mexico (97°W-99°W). We found no evidence for population-specific, parallel migration routes. Most individuals (72%) overwintered in Colombia. The remaining individuals overwintered in Venezuela.ConclusionsOur results demonstrate convergence of migratory routes around a migration barrier for individuals originating from widely distributed breeding areas. Further, we suggest the potential importance of habitat around the Gulf of Mexico during migration and Andean forest in Colombia as overwintering habitat for this threatened species. Future research should be directed at understanding how these areas are used by Canada Warblers.
Highlights
To effectively conserve migratory species, the entire range encompassed by their annual life cycle needs to be considered
We considered the effect of the different sites (Alberta, Manitoba, Québec or New Hampshire), geolocator types (W30, W50 or P30), harness types, ages at deployment (after second year (ASY) and second year (SY)) and deployment year (2014 or 2015)
We demonstrate that fall migration routes in Canada Warblers largely overlapped for three widely distributed breeding populations
Summary
To effectively conserve migratory species, the entire range encompassed by their annual life cycle needs to be considered. Recent technological innovations allow for year-round tracking of migratory songbirds by using archival light-level geolocators [7,8,9]. These units record time of day and light-level data which together can provide locations for each day that the unit is on the bird. Tracking species-at-risk year-round can yield new insight into the migratory and overwintering ecology of the species, providing invaluable information to effectively manage declining populations and determine conservation priorities [7, 9, 12,13,14]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
