Wind farms are killing bats in Nova Scotia, say researchers

With many wind farms under development in Nova Scotia, experts say extra caution is needed to protect migratory bats from being killed by wind turbine blades.

The hoary bat, the silver-haired bat, and the eastern red bat were recommended for Canada’s species at risk list in 2023 due to wind turbine fatalities.

Researchers advocate that the three bat species be officially added to the endangered list, which would grant extra protections and regulations surrounding wind turbine development. 

“The threat of wind energy development and (bat) fatalities due to wind turbines was the threat that was the primary basis for those three species being assessed as endangered in 2023,” said Kathy St-Laurent, a species at risk biologist for Environment and Climate Change Canada. 

Unlike the hibernating bat species native to eastern Canada, the hoary bat, the silver-haired bat and the eastern red bat are all flying migratory species that spend their winters in the southern United States or Mexico. All three come to Nova Scotia in the summer. 

During migration, bats encounter the spinning blades of wind turbines.

Studies of dead bats near wind turbines have shown each active turbine kills about 10 bats per year. In 2016, roughly 47,400 bats were killed by wind turbines in Canada. The addition of new wind farms in Nova Scotia will likely add to this number.

Mersey River Wind farm in Queens County, for example, is expected to open in 2026. It will have 33 turbines and account for about 45 per cent of the electricity purchased by Halifax Regional Municipality.

Lori Phinney, a representative with Mersey Tobeatic Research Institute, an organization that studies and advocates for Nova Scotia bats, said Mersey River Wind has been collaborating with the institute to do bat monitoring in the area and further protect bat populations.  

Mersey River Wind did not respond to The Signal’s request for an interview. 

Scientists predict that bat fatalities from wind farms will increase to about 166,000 bats per year by 2031 if new regulations aren’t enacted. 

“Wind power generation has increased markedly over the last decade or two in both Canada and the U.S. and is projected to increase to meet our green energy targets, including in the offshore environment,” said St-Laurent. “This is a threat that’s currently present and expected to get higher even in the future.” 

Ecosystem services

“Bats in general, provide ecosystem services,” St-Laurent said. “These services have economic and ecological benefits.”

When white-nose syndrome, a fungus that affects bats’ ability to hibernate, decimated bat populations in North America, people began noticing more insect pests on their properties, especially farms.  

“There’s been a recent study that showed increased infant mortality rates after the bat populations crashed due to white-nose syndrome,” she said. “They linked this to increased pesticide use, because there’s a lot fewer bats eating insects.”

Migrating bat populations were spared from white-nose syndrome, which killed about 90 per cent of the hibernating bat species in North America, because migratory bats fly to warmer climates in winter instead of hibernating. 

However, now wind turbines are killing enough migratory bats that, like the hibernating bats, are in danger of going extinct too. 

Fatal attraction 

Sepidar Golestaneh, a Nova Scotia bat researcher from University of Waterloo, said it’s strange that bats, with such strong echolocation, aren’t detecting something as big as a wind turbine and avoiding the blades. 

“I don’t know how their sonar plays into this, and people are still actively researching this, but bats are actually attracted to turbines, which is where a lot of people are really confused,” Golestaneh said.

Researchers hypothesize several reasons migratory bats are attracted to the windfarms. It could be an abundance of insects around turbines, or something to do with the air pressure change created by the speed of the spinning blades. 

“It’s still something that people are trying to figure out,” Golestaneh said, “why these bats are actually going towards wind turbines and are attracted to them.” 

With wind farms becoming more popular as eastern Canada moves away from fossil fuels, St-Laurent said it’s important for the migratory bats to be federally listed as endangered, so researchers and wind farms can work collaboratively to stop these mass bat deaths. 

 “Wind energy is an important piece of our move towards non-emitting energy sources and advancing climate change objectives,” St-Laurent said.

“Climate change can potentially worsen conditions driving some of the biodiversity loss and specific risks in the first place. So, I think really trying to figure out ways to advance both, and balance both renewable energy development — and climate change targets — with wildlife and bat recovery.” 

Two ways to balance protecting migratory bats and continue wind farm energy development is first, siting wind farms away from where bats frequent, and second, curtailment, where wind turbines are turned off or slowed down during times of bat migration. 

St-Laurent said siting can reduce bat deaths up to 50 per cent and curtailment can reduce them by up to about 80 per cent.