Behavior of Bats at Wind Turbines
Bat fatalities at wind turbines peak during low wind conditions and primarily involve tree-roosting bats. To investigate the reason for this pattern, USGS researchers and colleagues used thermal surveillance cameras, near-infrared video, acoustic detectors, and radar to monitor bat behavior at a wind farm in Indiana from July to October 2012. During periods of low wind, more bats approached turbines than during periods of high wind. As wind speeds increased, bats more frequently approached turbines from a downwind direction, but only when turbine blades were not turning.