In the process of creating sustainable energy, wind turbines across the United States are also taking a toll on a species that is vital to our ecosystem: bats.
More than 600,000 bats fell victim to the turbines in 2012, according to a new study. The turbines spin at up to 179 miles per hour, rising hundreds of feet into the air.
While many Americans consider bats to be pesky or scary, they serve a vital ecological role. They eat a tremendous number of flying insects and they help pollinate crops, such as peaches and avocados.
Published in the journal BioScience, this University of Colorado study analyzes records of dead bats found near the wind generators.
"Dead bats are being found underneath wind turbines across North America," wrote biologist Mark Hayes. "This estimate of bat fatalities is probably conservative."
The most deaths are occurring in the Appalachian Mountains, especially in Buffalo Mountain, Tenn., and Mountaineer, W. Va.
The numbers could be even higher, Hayes notes, because many bat carcasses are likely carried away by scavenging animals before the researchers are able to collect them.
He added that there is little information available for bat mortality along the Sierra Nevada and Rocky Mountain ranges. When there was information available, he used the lowest numbers. Previous estimates ranged from 33,000 to 880,000 deaths each year.
The bat population is already threatened by white-nose syndrome, a fungal disease that has been confirmed in 22 U.S. states and 5 Canadian provinces and affects 7 of the country's 45 known bat species, including two that are considered federally endangered.
First recorded in 2006, it has killed 90 to 100 percent of the bats in specific caves.
The population is slow to recover from these threats because bats give birth to one pup each year, and, Hayes told ScienceNow, the mortality rate for young bats is high.
In 2003, a number of organizations came together to form the Bats and Wind Energy Cooperative (BWEC). With representatives from Bat Conservation International, the U.S. Fish and Wildlife Service (USFWS), the Energy Department's National Renewable Energy Laboratory and the American Wind Energy Association, BWEC is working to redesign the turbines in order to have a smaller impact on the bat populations. So far, the cooperation has worked out acoustic adjustments and operational changes.