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- Title
Fall migration and breeding origins of Canada Warblers moving through northern Colombia.
- Authors
Cárdenas‐Ortiz, Laura; Bayly, Nicholas J.; Colorado Z., Gabriel J.; Hobson, Keith A.
- Abstract
Canada Warblers ( Cardellina canadensis) are long-distance Neotropical migrants, but little is known about their migratory behavior and ecology. We examined the fall migration of Canada Warblers at two sites, Darién and the Sierra Nevada de Santa Marta, in northern Colombia from 2011 to 2015 using constant-effort mist-netting. Our objectives were to determine: 1) breeding origins and connectivity patterns, 2) migratory pathways, 3) the phenology of migration, 4) possible differences in movements between ages and sexes, 5) their body condition when arriving in Colombia, and 6) evidence of stopover and refueling. Stable hydrogen isotopes (δ2Hf) in flight feathers were analyzed to estimate breeding origins of captured Canada Warblers in North America. The δ2Hf values revealed that most Canada Warblers captured in the Darién likely originated from the central and northeastern regions of their breeding range. The capture of all but one of 162 Canada Warblers in the Darién also indicates a migration route through Central American rather than across the Caribbean Sea. Most captured birds were hatch-year birds (91% vs. 9% after hatch-year birds), and we captured more females (67%) than males (33%). Canada Warblers migrated through the Darién from 20 September to early November, with most arriving in mid-October. Most (89%) individuals arrived with low fuel reserves. These results combined with estimated flight ranges revealed that 46% of the individuals captured in the Darién likely needed to refuel to continue migrating, whereas 31% could continue 50 to 200 km beyond our capture site. However, no individuals were recaptured so stopover duration could not be determined. Canada Warblers may adopt a strategy of 1-d stopovers and short flights or, alternatively, the Darién may represent low-quality habitat and birds quickly left our study site in search of suitable habitat. Further study is needed to determine the possible importance of other (montane) habitats for Canada Warblers in the Darién region to prioritize conservation actions.
- Subjects
LATIN America; EMIGRATION &; immigration; BREEDING; CANADA warbler; HYDROGEN isotopes
- Publication
Journal of Field Ornithology, 2017, Vol 88, Issue 1, p53
- ISSN
0273-8570
- Publication type
Article
- DOI
10.1111/jofo.12186