One of Europe’s most common types of bat ‘may be attracted to wind turbines’, study suggests

The activity of common pipistrelle bats was found to be around a third higher at the turbines than control locations.

One of the most abundant bats in Europe may be attracted to wind turbines and this could be why so many are found dead around the continent’s wind farms, a study has suggested.

Researchers at the University of Exeter monitored the activity of common pipistrelle bats at 23 British wind farms and similar “control” locations close by without turbines.

They found activity was around a third higher at the turbines than the control locations and that two-thirds of occasions of high activity were recorded around the turbines.

While the precise reason for such activity remains unclear, the team suggested it could be that the bats are attracted to the turbines themselves.

Another possibility could be the presence of more of the bats’ insect prey around the turbines, the researchers added.

Bat fatalities

The team, whose findings have been published in the journal Scientific Reports, said their work probably explained the “high fatalities” of common pipistrelle bats at some European wind farms.

“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,” said Professor David Hosken, of the University of Exeter.

“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.”

Professor Hosken said their findings helped explain why environmental impact assessments carried out before the installation of turbines were poor indicators 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,” he said.

“Ongoing monitoring is required, and measures such as minimising blade rotation in periods of high collision risk are likely to be the most effective way to reduce fatalities.”

The study also monitored soprano pipistrelle bats but found no conclusive evidence that this species was more active around turbines.

Activity ‘variable’

Professor Fiona Mathews of the University of Sussex, who led the research, said bat activity around wind turbines was “very variable”.

She said that during periods of high wind – where most energy is generated – bat activity was low and so there was little risk to the animals.

“In contrast, there can be high activity at turbines on nights with light winds and warm temperatures,” she said.

“Most of the attraction to turbines appears to be happening on these high activity nights.”

She said stopping blades from rotating when no energy is being produced would help minimise risk to bats, adding such an approach was a “win-win situation” as little electric generation is lost during such periods.

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