Isotope fingerprints in feathers reveal songbirds' secret breeding grounds

Myrtle warblers breed across much of Canada and the eastern United States, but winter in two distinct groups -- one along the Atlantic and Gulf coasts, another along the US Pacific Coast. They are also one of the few breeds of eastern warbler that have been able to extend their range into the far northwest of the continent.

"The Pacific Coast warblers migrate through the Vancouver area, but it's been a bit of a mystery exactly where they breed over the summer," says David Toews, who began the research while a graduate student at the University of British Columbia (UBC). Read more.