WASHINGTON – When it comes to global warming, the canary in the
coal mine isn't a canary at all. It's a purple finch. As the
temperature across the United States has gotten warmer, the
purple finch has been spending its winters more than 400 miles
farther north than it used to. And it's not alone. An Audubon
Society study to be released today found that more than half of
305 birds species in North America, a hodgepodge that includes
robins, gulls, chickadees and owls, are spending the winter
about 35 miles farther north than they did 40 years ago. The
purple finch was the biggest northward mover. Its wintering
grounds are now more along the latitude of Milwaukee, Wis.,
instead of Springfield, Mo. Bird ranges can expand and shift for
many reasons, among them urban sprawl, deforestation and the
supplemental diet provided by backyard feeders. But researchers
say the only explanation for why so many birds over such a broad
area are wintering in more northern locales is global warming.
Over the 40 years covered by