Global Climate Change Makes U.S. Birds Shrink

Nearly one-third of U.S. bird species "are endangered, threatened or in significant decline," due to global climate change, Department of the Interior chief Ken Salazar said Thursday.

Salazar issued a report, "The State of the Birds: 2010 Report on Climate Change", created by the U.S. Fish & Wildlife Service in collaboration with conservation groups. In it, researchers looked at five factors affecting bird species and weighed them against climate change effects. The factors were migratory vulnerability, breeding ground vulnerability, specialization to particular ecological niches, ability to move home terrains and breeding pattern robustness, USA Today reported.

Birds in arid regions and forests show less vulnerability to climate change, but the report says many species struggling in arid regions now, including the endangered golden-cheeked warbler and black-capped vireo in Texas, could be further imperiled by shifting climate conditions.

"Birds are messengers that tell us what is going on in our environment," Salazar said. "For too long, in my view, we have stood idle as the climate changes and as the crisis has grown."

A 2009 report on bird populations found nearly a third of the nation's 800 bird species are endangered, threatened or in decline due to challenges such as the loss of wetlands, commercial hunting and pesticides, The Associated Press reports.

Of the 186 species of birds that breed across the state, a third of the population has either increased or leveled off since the 1960s, said Michael Bartlett, president of New Hampshire Audubon. There isn't enough data to detect a trend in about one-third of the species. What's concerning, Bartlett said, is the remaining third, which indicates a steady, long-term population decline. Some species in that category have dropped rapidly, he said, Concord Monitor informs.