Wind turbines could be killing tens of thousands of bats a year, a new study has found.
Scientists think that bats may turn their sonar off at large heights because they do not expect to run into anything. Currently, there are some wind turbines in the UK taller than London’s tallest buildings.
Researchers from the University of Exeter used sniffer dogs to search out bodies of stricken bats at 29 wind farms that had undergone risk assessments to prevent bat death. They found that 194 bats per month were killed in collisions with wind turbines. However, the number is likely to be higher due to carcasses being carried off by predators.
All UK species of bat are protected by UK law. 18 of the 29 risk assessments reported that building a wind farm in the area was unlikely to affect protected species. However there is concern that bats may actually change their behaviour once the turbines are built. Some insects and moths are drawn to the turbine blades, and bats might follow them to hunt or to explore the structure.
Dr Fiona Mathews, lead author of the research that was published in Current Biology, said: “The sorts of mitigation that have been used, like moving the turbine a bit further away from woodland, just wasn’t doing the job.”
Now scientists are suggesting that the turbines should be switched off during peak migration and breeding seasons, such as summer nights.
The main casualties of the turbine collisions are two common species of bat called the Common Pipistrelle and Soprano Pipistrelle. These tiny bats have reddish-brown fur and blackish-brown ears.
Dr Paul Lintott, first author on the Current Biology paper, reminds us that although windfarms do kill bats, it is important to remember the wider benefits of renewable energy and the overall positive impact it will have on global biodiversity.
He says that: “By focusing resources on stopping turbines during high risk periods we should be able to minimise the collision risk to local bat populations whilst also benefiting globally from the transition to a greener economy.”
Dr Fiona Mathews adds: “At the moment, tens if not hundreds of thousands of pounds are paid on infrastructure projects all the time to do ecological surveys, with nobody actually doing any follow-ups to see whether they’re effective or not.
“What we want is something that actually works for conservation rather than it just being a box-ticking exercise.”
It seems clear that bat populations must be further monitored after wind turbines are put in place. Furthermore, wind turbines should be turned off during periods of high bat activity in order to protect the vital species.
Image: Andy Morffew