| While the increase in wind energy has greatly reduced the use of fossil fuels, there have also been major negative impacts on migratory tree bat populations. Species often impacted by wind farms include the hoary bat (Lasiurus cinereus), the eastern red bat (Lasiurus borealis) and the silver-haired bat (Lasionycteris noctivagans). Previous research indicates that wing morphology and bat body size do not allow evasive maneuvers to avoid wind turbine blades. While the exact nature of these occurrences is still not clear, higher rates of mortality occur during seasonal migrations when they are most likely to encounter wind farms. Our study focused on four single-standing turbines found in Erie, IL, Sherrard, IL, and two in Geneseo, IL. We searched for dead bat carcasses within a 48 m radius of the turbine base to determine frequency of bat mortality each week from 6/8/2015 to 10/31/2015 to include summer roosting and fall migration periods. Dead bats located within the circular plot were marked with GPS, and species were identified. Anabat acoustic detectors were used to determine species present in the surrounding habitat.;Forty-three carcasses were found at the sites, increasing in August, and continuing through the fall migration season. Average wind direction, wind speed (NOAA), and date were modeled using nonparametric multiplicative regression. Our results indicated that the interaction of increasing average wind speed, wind direction, and date, has a significant impact on bat mortality near single standing wind turbines. Date was important, indicating an increase in mortality in late summer and fall during the migration period. This illustrates that the increased passage of bat species during the fall migration, particularly during high wind, cause an increase bat mortality. Wind turbines are typically set to function only during high wind speeds. Bats of this region typically fly during wind speeds averaging no more than 8 m/s, so passage of bat species during high wind was not expected. |
