Each year, migratory birds journey from their breeding grounds to their wintering grounds, making pit stops along the way.
Now a first-ever University of Guelph study has uncovered precisely when and where tree swallows – a common migratory bird – stop during flights that can span more than 3,500 kilometres across North America. The findings tell us more about migration and help us understand threats faced by the birds throughout the journey, said Prof. Ryan Norris, Department of Integrative Biology.
“Migratory birds are really just visitors up here,” said Norris, who worked on the study with post-doc researcher Elizabeth Gow, which was conducted in Norris Lab. “They breed for a couple of months and then spend the rest of the year in migration and at their tropical wintering grounds. If we are to make any progress towards understanding what is causing their declines, we need to know how these stages of the annual cycle are linked.”
Published recently in the journal Proceedings of the Royal Society B, the study is the first to track the timing of 12 geographically distinct North American breeding populations of tree swallows across the continent. Previous studies have followed just one population at a single latitude.
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Image via University of Guelph.