Human efforts to help the planet with cleaner energy sources comes with a price. There have been numerous studies of birds killed by wind turbines, but there is also another victim: bats. Many different species of bats are killed by wind turbines worldwide and there have been high fatalities of common pipistrelle bats seen at some wind farms across Europe. In fact, common pipistrelle bats account for more than half of all bat fatalities at turbine sites in Europe.
Researchers set out to examine just how widespread the problem of bats killed by wind turbines is, and to try and figure out why bats are killed even when wind turbines are constructed in areas where there are typically low concentrations of bats.
The activity of common pipistrelle bats was monitored at 23 British wind farms and similar “control” locations close by without turbines. Activity was around a third higher at turbines than at control locations, and two thirds of occasions with high activity were recorded at turbines rather than the controls.
As for why the bats are flying near the wind turbines even in areas with low concentrations of bats, the scientists concluded that the reasons for this are unclear. Possibilities include attraction to the turbines themselves, or the presence of more of the bats’ insect prey around turbines.
“We know bats are killed by turbines worldwide, and reducing these fatalities is essential to ensuring a global increase in wind energy with minimal impact on bats. To do that, we need to understand whether bats are actively attracted to, indifferent to, or repelled by, the turbines at large wind-energy installations.
“Our findings help explain why Environmental Impact Assessments conducted before the installation of turbines are poor predictors of actual fatality rates. Turbines are generally built in areas where bat activity is thought to be low, but this may not be an effective strategy if bats are attracted once turbines are built.
“Ongoing monitoring is required, and measures such as minimizing blade rotation in periods of high collision risk are likely to be the most effective way to reduce fatalities.”
-Professor David Hosken, researcher, University of Exeter.
Journal Reference: Suzanne M. Richardson, Paul R. Lintott, David J. Hosken, Theo Economou, Fiona Mathews. Peaks in bat activity at turbines and the implications for mitigating the impact of wind energy developments on bats. Scientific Reports, 2021; 11 (1) DOI: 10.1038/s41598-021-82014-9