Global warming imperils half of North America's bird species, says Audubon report

A report by the National Audubon Society says that the habitats for more than half of North America's 588 bird species will shrink significantly or move to an entirely new location.

As the world gets warmer, the Baltimore oriole will no longer be found in Maryland. The Mississippi kite will move north, east and pretty much out of its namesake state. And the California gull will mostly be a summer stranger to the Golden State.

Those are among the conclusions in a new National Audubon Society report that looks at the potential effects of global warming on birds by the year 2080.

"This will spell trouble for most birds," said Gary Langham, the society's chief scientist and vice president.

Over the next six decades or so, the critical ranges of more than half the 588 North American bird species will either shrink significantly or move into uncharted territory for the animal, according to Langham's analysis.

While other studies have made similar pronouncements, this report gives the most comprehensive projections of what is likely to happen to America's birds.

The report says that in a few decades, 126 bird species will end up with a much smaller area to live in, which the society says will make them endangered. An additional 188 species will lose more than half their natural range but relocate to new areas. Those moves will be threatening to the birds' survival, too, because they will be confronted with different food and soil, bird experts said.

Other birds, including backyard regulars like the American robin and the blue jay, will fly in even more places, the report says. And some of the biggest potential winners aren't exactly birds that people like — species such as the turkey vulture, the American crow and the mourning dove, which will expand their ranges tremendously.

"If you want to know what the climate change future sounds like, it sounds a lot like a mourning dove," Langham said. Some people find annoying the singing of the mourning dove, which will more than double its range.

Langham used bird survey data in summer and winter from 2000 to 2009 and correlated it to climate conditions to come up with simulations of how bird ranges will change. He then tested the simulations against past data from 1980 to 1999, and they worked. Then he used United Nations carbon pollution scenarios from 2007 to project bird ranges in 2020, 2040 and 2080.

The report is not yet peer-reviewed, which is crucial in science. It has been sent to a scientific journal but has not yet been accepted. However, Langham said it is based on a report Audubon did last year that was commissioned by the U.S. Fish and Wildlife Service.

Duke University ecologist Stuart Pimm dismissed the study as too general, poorly executed and not that new. But other scientists, such as Stanford University biologist Terry Root, said the Audubon report makes sense and looks trustworthy. A third biologist, A. Townsend Peterson of the University of Kansas, faulted some of the methods used but praised the overall comprehensiveness of the study.

"It's very scary," Root said. "People need to stand up and take note."

On Tuesday, several federal agencies, Cornell University and a number of private organizations will release a separate U.S. "state of the birds" report, and the outlook will be bleak.

Cornell Lab of Ornithology director John Fitzpatrick wrote in a preview last month in The New York Times that 230 species "are currently in danger of extinction or at risk of becoming so" and that two dozen common birds, such as nighthawks, are showing "early warning signals of distress."

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