PHILADELPHIA (CBS) - Wind turbines are welcomed by clean energy advocates but wildlife enthusiasts are worried about their unintended consequences.  Those spinning blades are proving deadly for nature’s own pest control agent.

Some people don’t like bats, but they are powerhouses of pest control, each one eating thousands of bugs each night.   That’s not only good for backyard barbecuers but is also economically important for farmers.

So, it is a problem to Pennsylvania Game Commission (PGC) wildlife management supervisor John Morgan that wind turbines are killing thousands of bats a year in Pennsylvania.

“A single turbine may contribute to the death of twenty, thirty bats a year,” he says.

Morgan says the bats are drawn to turbines while chasing bugs, who are in turn attracted by the heat the turbines generate.

“The bat is just kind of knocked down by the pressure change and not necessarily the physical movement of the turbine hitting the bat,” he explains.

Morgan says the PGC is now trying to figure out how to reduce bat mortality around turbines even though they’ll have to depend on turbine companies to take steps that could end up costing them more money.

Reported by Pat Loeb, KYW Newsradio 1060