Wind turbines lead to decline in bat population

LETHBRIDGE, Alta. -

Canada’s three migratory bats are now officially recognized as endangered species.

The eastern red, silver and hoary bats have seen a significant drop in numbers.

Collisions with wind turbines have played a major role in the population decline.

“Wind energy is booming in Alberta as elsewhere and bats and wind turbines don't get along very well. The wind turbines kill a lot of bats. In fact in Alberta it kills more bats than it does birds,” said University of Calgary professor of biological sciences Dr. Robert Barclay.

Wind turbines are a common sight in southern Alberta, taking advantage of the region’s windy conditions.   

Bats don’t need to hit a turbine to be killed by one, just getting close can be deadly.

Dr. Cori Lausen, director of bat conservation for the Wildlife Conservation Society Canada, said “all they really have to do is get close to these blades and that's a low pressure zone and that literally causes the blood vessels in their lungs to explode. Sort of like a scuba diver coming up too quickly.”

Between 500,000 and a million bats are killed each year by wind turbines across Canada and the United States.

Collisions with wind turbines have played a major role in the population decline.

But because migratory bats travel at night and typically not in large groups, tracking the number of bats in any one region or how many are killed by turbines is challenging.

“It's funny when I get asked questions about how many bats there are,” said Dr. Lausen. “We have a hard time counting trees, and they don't move. So it's been very difficult to estimate bat populations.”  

Bats play an essential role in pest control, pollinating plants and dispersing seeds. Fewer bats forces farmers to use more pesticides, which also harms bat populations.

According to experts slowing down turbines in low wind conditions especially at night can help save the bats.

Dr. Barclay said “When the wind speeds are low, shut down the turbines, and see how many fewer bats you kill. In experiments we did with several Alberta companies, (we saw) 50 per cent less fatalities of bats.”

 Bats that hibernate are facing their own challenges.

An outbreak of white nose syndrome across North America has killed significant numbers of bats in hibernation roosts.