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Canaries in the coal mine?

Illinois' declining bird population

If you had gone birding 40 years ago just outside of Chicago, you would have seen a vastly different landscape than what you see today. Dotted among small- and medium-size family farms would be a mix of prairie, wetland, oak savanna and oak woods. Those habitats featured such native plants as bur oaks, quackgrass and blue joint grass, which fostered animal species such as bobolinks, a black grassland songbird with a custard-colored nape and white back, and red-headed woodpeckers.

Yet as Chicago's population has pushed outward, a number of bird species native to Illinois have seen their local populations decline in the past 40 years, according to a National Audubon Society study released in June. The bobolink and red-headed woodpecker populations have dropped 97 percent and 71 percent respectively.

And with the continued destruction of birds' natural habitats, coupled with global warming, at least 400 of the world's 8,750 bird species could see significant declines or extinction by 2050, according to a separate study conducted by biologists at the University of California, San Diego and Princeton University.

For birders, those declines mean their days of spotting a slew of colorful, charismatic species may be dwindling. But the studies' implications may also serve as the figurative canary in the coal mine, suggesting that our ecosystems are becoming increasing inhabitable, says Steve Packard, Chicago-area Audubon director.

"The species that are declining the fastest are the ones that require high-quality ecosystems," Packard says. "When Rachel Carson [author of the landmark book Silent Spring] pointed out that birds were dying from chemicals, the only reason she was pointing to birds was that it was birds that died quickest. What was unhealthy for bird species were the same things that ultimately caused cancer and birth defects in humans."

The Audubon report, which combined 40 years worth of volunteer "citizen scientists'" annual Christmas bird count data with the U.S. Geological Survey's breeding bird survey data, was the first of its kind for the non-profit environmental group. The report's Illinois findings mirrored those nationwide, as the average population of the most common bird species in steepest decline have seen their average population drop 70 percent since 1967. The degree to which the populations have fallen surprised even Packard.

"It's a whole different level of shock when you realize that the same things happening here are happening everywhere," Packard says. Other research, such as the University of California, San Diego/Princeton study, which combined four projections of future global warming, agricultural expansion and human population growth with current geographic ranges of the world's bird species, found that the birds most at risk are predominately located in the tropics, due to deforestation. In turn, that deforestation may contribute to global climate change--especially at latitudes higher than 30 degrees (Chicago is located at 41.9 degrees latitude)--which is already threatening such common species as the American redstart.

"Birds in the Philippines, Indonesia and other countries have been losing habitat in a massive way," says Walter Jetz, the study's lead author. "And we'll continue to see that in the next 10, 20 years, unless we change how land is managed."

But the need to do something about changing land use is not limited to the tropics. Throughout the Chicago region, species have clung to their ever-shrinking habitats, which have been displaced by suburban sprawl. Forest preserves are crawling with such non-native species as yellow and white sweet clover and reed canary grass.

However, there is a bright spot, says Packard, noting that a number of local conservation efforts have begun to successfully reverse the trend by uprooting non-native plants and animals out of the area's forest preserves, removing litter and seeding fields with native prairie plants and grasses.
In just a few years, Patricia Hayes, who has worked on the conservation effort at Orland Grassland, has seen the beginning of a turnaround at the 750-acre forest preserve. Among the species that she's seeing more often are eastern meadowlarks and grasshopper sparrows.

The area has changed dramatically since Hayes moved to Orland Park in 1986. "In a matter of 20 years, when you would exit the expressway, not even a mile from Orland Grassland, you could see for miles," Hayes says. "It was dotted with farms and was rolling and open...now when you get off at Wolf Road you have to wait two lights before you can get through the intersection."

That increased congestion makes it even more essential to return the land to its natural landscape, says Packard. "After all, what's good for the birds is good for us."

Published: August 07, 2007
Issue: Fall 2007