It’s a little Animal Planet, a little CSI. A new study conducted by the University of Wisconsin Madison looked into the cause of death of countless numbers of bats found near wind turbines. The study was funded by Invenergy and Wisconsin Focus on Energy and recently discussed on the University of Wisconsin’s news site.
Researchers conducting the study had two culprits in mind for the cause of death: barotrauma, caused by bats flying through different pressures created by the turbines which causes the bats internal organs to explode and blunt-force trauma from bats colliding directly with turbine blades or poles. While bats are able to fly around non-moving objects, the speed of the blades makes reaction time difficult for bats to avoid.
Researches used veterinary diagnostic techniques along with x-rays, tissue analysis, and gross necropsy to support or rule out their assumptions. Three-quarters of the bats studied had broken bones and ruptured organs. About half of the bats examined had middle and/or inner eardrum ruptures.
“We still don’t know exactly why bats are being killed — why the bats can’t see such a large thing protruding from the landscape, or what is possibly attracting the bats,” UW Professor David Drake said in the new article, “but now that we know direct causes of death we can start thinking about how to redesign turbine blades to have a smaller pressure differential or identify other cost-effective mitigation strategies that would minimize damage to bats.”
The full study, “Investigating the causes of death for wind-turbine associated bat fatalities,” is published in the October 2011 issue of the Journal of Mammalogy. It also isn’t the first study to look into this matter – one last year found that a slight alteration in turbine operation practices can have a big effect in reducing bat fatalities.