A new study from the University of Iowa and Illinois State University contradicts a widely-held assumption that wind turbines can kill bats by causing abrupt changes in air pressure in their lungs.

Researchers used forensic pathology to identify the cause of death of bats found near wind turbines. They found that lung tissue in bats can deteriorate quickly after death, can mimic what’s known as barotrauma – damage to the lungs caused by differences in air pressure.

“This study raises some serious questions about the foundation of barotrauma theory in wind farm bats and simultaneously demonstrates by multiple lines of evidence that the collision theory is the basis for most of these deaths,” said University of Iowa scientist David Meyerholz in a news release.

Bats provide critical pest control for farmers, with an economic benefit of as much as $3 billion per year. While wind farms are by no means the only threat that bats face, the research will help efforts to limit the impact.

“Clarifying the cause of bat deaths focuses future studies on understanding why migrating bats are prone to these collisions and will guide development of appropriate mitigation systems to reduce these deaths,” Meyerholz said.

The study will be published in the March issue of the journal Veterinary Pathology.