Published: March 08, 2009 09:29 pm      

For the birds? Report says global warming forcing shift in migratory pattern

Scientists for the National Audubon Society say “new and powerful” evidence compiled over the last 40 years suggests that nearly 60 percent of the 305 species of birds that winter in North America are shifting their ranges northward due to the impact global warming has on their ecosystems.

According to a news release by Audubon officials, their scientists analyzed citizen-gathered data from the past 40 years and concluded the birds have shifted their ranges to the north by an average of 35 miles since 1968.

“Movement was detected among species of every type, including more than 70 percent of highly adaptable forest and feeder birds,” the release said.

Audubon scientists believe the 177 species of birds which have moved northward reveal “an undeniable link to the changing climate” because of the correlation to the increase in long-term winter temperatures.

“Birds are showing us how the heavy hand of humanity is tipping the balance of nature and causing ecological disruption in ways we are just beginning to predict and comprehend,” Audubon director of bird conservation and co-author of the report, Greg Butcher, Ph.D., said.

“Common sense dictates that we act now to curb the causes and impacts of global warming to the extent we can, and shape our policies to better cope with the disruptions we cannot avoid.”

Among the report’s findings are:

- Purple Finch, Pins Sisken and Boreal Chickadee have retreated into the Canadien Boreal, moving their ranges an estimated 211 to 313 miles.

- Red-breasted Merganser, Ring-necked Duck, and American Black Duck, normally found in the south, have shifted their ranges in some cases up to 244 miles.

- Only 10 of 26 grassland species moved north significantly, while nine moved south. The study suggested species such as the Eastern Meadowlark, Vesper Sparrow and Burrowing Owl were “likely unable to move” because of the disappearance of grassland habitats.

Butcher claims that some species could even become extinct if global warming trends continue unabated.

“Experts predict that global warming will mean dire consequences, even extinction, for many birds species, and this analysis suggests that the process leading down that path is already well under way,” he said.

Butcher and other Audubon officials are urging lawmakers to take action by “advancing policies that will drastically reduce global warming pollution, cut oil dependence in half, and invest in a clean energy future and the economic benefits it offers.”

“These birds are our ‘canaries in the coal mine’ and they’re telling us that we’d better do something fast to curb global warming and to protect habitat,” Audubon president John Flicker, said.

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Three Rivers Avian Center executive director Wendy Perrone said she has not personally seen a definitive correlation between global warming and bird migration and believes there are other factors which could be affecting the movement of birds. The non-profit organization located in Summers County focuses on wild bird conservation and education of ecosystem stewardship.

Perrone said she has not seen a massive change in bird migration in Summers County, with the exception of the Evening Grossbeak bird.

“I’m not saying global warming isn’t happening, but the changes in migration patterns could be due to other factors,” Perrone, said. “Loss of habitat is a contributing factor as well.”

Perinea said correlating all data taken from bird watchers “could be difficult.”

“The art of bird watching as a sport is fairly new and only dates back 50 years or so,” she said.

Audubon officials believe the new bird evidence will “help attract the attention and spark action among more than 40 million U.S. bird watchers,” including the tens of thousands who contributed to the Christmas Bird Count data which the report was based on.

Founded in 1905, the New York-based Audubon Society was named in honor of John James Audubon, a French-American naturalist who painted, catalogued and described North American birds in books written from 1827 to 1838.

On the net: www.audubon.org

— E-mail:

cgiggenbach@register-herald.com