The scope and severity of bat fatalities at US wind energy facilities

Wind turbines are a major source of bat fatalities in the United States, yet the magnitude and species-specific patterns of these fatalities have remained poorly quantified because monitoring has been site-specific, unstandardized, and not designed for landscape-level synthesis. In the most comprehensive analysis to date, we synthesized 499 postconstruction monitoring reports and developed a multispecies Bayesian hierarchical framework with an adapted N-mixture model to pool information across sites and estimate total fatalities for ten bat species across the conterminous United States from 1981 to 2024. Our analysis predicts approximately 18.7 million bat fatalities over this period, with substantially higher species-specific totals than previously estimated. Our framework provides a landscape-level analysis that can predict fatalities for unmonitored locations and years, identify landscape-level drivers of fatalities, produce a multidecade hindcast of cumulative losses due to wind energy, and map where species-specific risk is highest. Although limitations and uncertainty remain, the magnitude of predicted fatalities may be comparable to total losses from white-nose syndrome, another major threat to North American bat populations. These threats affect largely different species, suggesting their impacts may compound, but updated population-level impact assessments could reveal potential cumulative effects. Our estimates of species-specific covariate relationships with rotor-swept area, ground clearance, land cover, and proximity to rivers, highlight opportunities to help reduce impacts through wind turbine design and siting. This work establishes a generalizable landscape-level framework for evaluating wildlife fatalities at wind energy facilities and highlights how coordinated monitoring, data sharing, and population-level impact assessments could further inform conservation efforts.