When Bats Look for Meals Near Wind Power, Bats Die

Ozzy and other search dogs helped researchers locate bats near wind turbines. Credit Victoria Stent

Wind power can help the world fight climate change, but it’s not so great for bats.

A new study of wind turbines in Britain found that each turbine killed one to two bats each month on average, with some killing more than 60. The researchers said that the efforts that are required in many countries to assess the environmental effect of planned wind farms have proved faulty and inadequate in measuring the risk to bats. There are more than 300,000 wind turbines around the world.

The risks to birds of the blades of wind turbines are becoming well understood, but the risk to bats, while known, has been poorly defined until now, said Fiona Mathews, lead author of the study and an assistant professor of mammalian biology at the University of Exeter in England. Bats, she said, might be attracted to turbines, whether because of the noise the machines make or the bugs that are trapped in the air movement: “It’s a ready food supply.”

Her team found bat casualties in unexpected places like high-altitude spots, she said.

Finding the bats, which are small and not colorful, presented special challenges. Using specially trained bat-sniffing dogs, the researchers found the hard-to-spot bat corpses at the bases of turbines at 46 wind farms around England. Dr. Mathews said she contacted an expert who trains dogs to sniff out bodies, bombs and the like for bat duty. “He just killed himself laughing,” she said, and then he told her, “This is the funniest thing anybody’s ever asked me to do.”Photo

Dr. Mathews, who is also the chairwoman of the Mammal Society, a conservation group in England, said that the research in no way suggested that renewable power was a bad thing, but argued that wind power companies should take action to minimize the damage to bats, which pollinate plants and consume pests like mosquitoes. The risk is higher at times of low wind, in part because bats are less likely to take to the air during a hard blow; because turbines are not generating much power anyway during those times of relative calm, stilling the blades or shifting their pitch to limit motion could save many bats, as could curtailing operation during peak bat periods of the year. “You can make a huge difference in the number of bats you’re killing,” she said.