ScienceNOW: For decades, researchers have noticed that mangled birds litter the ground surrounding wind turbines, and recently they've found that dead bats actually outnumber the birds, by as many as four times in some places. This was a surprise, as bats' sonar should allow them to detect moving objects even better than they do stationary ones. The findings suggest a sudden drop in air pressure that ruptures blood vessels in the bats' delicate lungs, says Erin Baerwald, an ecology graduate student at the University of Calgary in Canada.