Abstract
At a time of growing concern over the rising costs and long-term environmental impacts from the use of fossil fuels, wind energy has become an increasingly important sector of the electrical power industry. However, large numbers of bats are being killed at utility-scale wind energy facilities, and these fatalities raise important concerns about cumulative impacts of proposed wind energy development on bat populations. We discuss our current state of knowledge on patterns of bat fatalities at wind facilities, present new information on cumulative fatalities in the USA and Canada, and present findings from mitigation studies. Given the magnitude and extent of fatalities of bats worldwide, the conservation implications of understanding and mitigating bat fatalities at wind energy facilities are critically important.