Wind turbines are responsible for the deaths of between 10,000 and 40,000 birds each year, according to the American Bird Conservancy. Debate over the significance of the threat turbine blades pose to migratory birds is about as old as the concept of wind farms themselves. It began in Altamont Pass, Calif., site of one of the first U.S. wind farms, where there were more than 4,000 turbines. Hundreds of bird carcasses were found on the farm grounds, leading bird conservationists to propagate information that wind turbines were inherently deadly to birds.

Some say counting carcasses isn't enough. That's why Illinois is changing the way it wants studies of wildlife around wind farms to be performed as more of the clean energy installations are planned around the state. Previous research has been based almost entirely on mortality counts, the process by which bird and bat carcasses are scooped up early in the morning within a several hundred foot radius of wind turbine bases. But studies now are aiming to determine a more long-range impact on avian and terrestrial creatures by examining how animals react to the sudden presence of a vertical structure soaring as high as 450 feet into the sky. The shift in practice comes as other mortality studies are under way in the area, but only a few have been completed in the state. ..."It's unfair to assume, I think, that there's no environmental effects from wind (energy)," said Keith Shank, an impact assessment specialist with the DNR. "Until we get some firm data, the problem is, people are making multimillion-dollar investments with insufficient information."

Illinois can expect bird deaths to grow as the number of wind turbines generating electricity grows. Jack Darin, president of the Sierra Club Illinois Chapter, discusses the findings of a Department of Natural Resources study that wind turbines used to generate electricity do result in the killing of birds.

Despite proof that birds and bats are being killed by the rotating blades of wind turbines, a new state report says more studies are needed to determine if anything should be done about it. ...But, the report did not call for any immediate action by the state. ''Until the impacts are better understood, regulatory action for wildlife protection is not recommended,'' the report noted.

In popular Halloween folklore, vampires are able to transform into bats. And, of course, fiction tells us that one way to kill a vampire, and thus the bat, is with a stake through the heart. But in areas around the United States, a new potential bat killer has emerged - wind turbines.