6.15.2007 12:00 AM

Common Birds in Drastic Decline

By Dan Shapley

A new study by the National Audubon Society has found that many of America's most well-known and well-loved birds are disappearing. Some species have declined as much as 80 percent. Loss of habitat is the biggest reason for the trend, as suburban sprawl, farming, mining, energy exploration and logging have radically altered the American landscape over the past 40 years. Grasslands, healthy, mature forests and wetlands are all in decline, in part due to human development and industry and in part due to the introduction of foreign, invasive plant species.

While declines in grassland species of the American Midwest have been documented before, certain boreal forest species now show new declines due, in part, to logging. Global warming, too, poses a serious threat, as the changing climate alters habitat, food and disease dynamics. For the first time, declines in birds on the tundra could indicate that global warming is already having an effect, according to the study's lead author, Greg Butcher.

“These are not rare or exotic birds we're talking about...these are the birds that visit our feeders and congregate at nearby lakes and seashores and yet they are disappearing day by day,” Audubon chairwoman and former EPA Administrator Carol Browner said. “Their decline tells us we have serious work to do, from protecting local habitats to addressing the huge threats from global warming.”

Species on Audubon's list of Common Birds in Decline have seen their populations plummet at least 54 percent since 1967. For a list of the hardest-hit birds, click here. The results have not been peer-reviewed, but the scientists plan to submit the study to a scientific journal for review. Some trends leading to the declines may become worse in the near future. Industrial-scale agriculture has greatly reduced grassland habitat, and the recent boom in ethanol — fueled by government subsidies — has led to a big increase in corn planting.

Audubon's Common Birds in Decline list stems from the first-ever analysis combining annual sighting data from Audubon's century-old Christmas Bird Count program with results of the annual Breeding Bird Survey conducted by the U.S. Geological Survey. These surveys are executed by volunteers around the country and world, who submit records of their observations. "This is a powerful example of how tens of thousands of volunteer birders, pooling their observations, can make an enormous difference for the creatures they care the most about," natural history writer Scott Weidensaul said in a prepared statement. "Thanks to their efforts, we have the information. Now all of us — from birders to policy makers — need to take action to keep these species from declining even further." Weidensaul said the decline of game birds — like scaup, pintail and grouse — shows that even species that are the subject of extensive planning and conservation efforts are suffering. That shows that "the time to save species is when they are still common." "Really," he said, "no species is safe from the sweeping landscape changes we're seeing."