While it may be assumed that these bats died due to collisions with the wind turbines, they also died from trauma linked to sudden changes in air pressure caused by the moving of the high-speed blades.
Mark Hayes of the University of Colorado led the study, published in BioScience, which shows that certain areas of the country, such as the Appalachian Mountains, witness higher mortality rates.
Based on the number of dead bats observed at 21 locations, Hayes conducted a statistical analysis to infer the probable number of bat deaths at wind energy facilities, correcting for their power capacities.
Hayes said that the estimate was a conservative one and that the number could be 50 percent higher.
He notes that bat populations are already under severe stress from climate change and disease, making the new number all the more important.
Bats are important for the ecosystem as they are insect-eaters and even pollinate some plants. While there is no actual estimate of bat populations in the U.S., it is hard to assess the impact of these deaths. Since bat population grow very slowly, because they produce only one offspring per year, this new revelation is worrisome.