Wind energy may be renewable, but it’s not completely innocent. Studies of birds meeting their fate at the blades of wind turbines are well-reported. But a 2007 study by the US National Research Council found bats have it even worse, with two bat species accounting for 60 percent of winged animals killed. The bats were turning up dead under wind turbines with no visible reasons for their death. Now, a new study helps explain the mystery: Their lungs burst. As NewScientist magazine reports, “the moving blades cause a drop in pressure that makes the delicate lungs of bats suddenly expand, bursting the tissue’s blood vessels. This is known as a barotrauma and is well-known to scuba divers.”
Researcher Erin Baerwald of the University of Calgary in Canada and her colleagues collected 188 dead bats from wind farms in southern Alberta. While only half showed direct contact with the windmill blades, 90 percent of them had signs of internal hemorrhaging.