Because:

…Thirty-five windmills at a wind farm in Pennsylvania have been shutdown at night since a bat was found dead under one of the turbines.

According to the Associated Press, the farm was forced to shut down the windmills during the night time hours, after the bat, an endangered species, was found dead in September.

By the way, you read the copy correct. We’re talking about one dead bat.

The wind farm was built by Gamesa Energy USA, and covers parts of Portage, Washington, and Cresson Townships in Cambria County, and part of Blair County, about 60 miles east of Pittsburgh.

A spokesman for Duke Energy, which now owns the wind farm, says it has an agreement with the U.S. Fish and Wildlife Service to determine whether bats are regularly being harmed by the windmills.

….The reduced generation of electricity from the wind turbines will decrease overall efficiency of the farm, thus causing the cost of this “green” energy source to be even more expensive for the consumer than it already is.

It’s not an uncommon problem.