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| 02/21/18

‘Sonic scarecrows’ could protect birds from wind turbines


US researchers may have found a solution to the problem that wind turbines pose to birds, potentially undercutting one of the arguments against this form of clean energy.

Wind energy can be part of the solution to climate change due to its low greenhouse gas emissions, but community resistance can arise due to noise or obstruction of views. Opposition also sometimes comes from birdwatchers.

In the UK, the Royal Society for the Protection of Birds (RSPB) broadly supports the development of wind energy, arguing that climate change poses the greatest threat to birds. But there are potential conflicts where wind farms are sited in locations of high activity for birds, especially endangered or rare species, such as major migration routes and important feeding, breeding and roosting areas. The RSPB regularly opposes construction of such farms in these types of locations, and highlights developments in Spain and California where it says poorly sited wind farms have caused major bird casualties.

A behavioural biologist with the Virginia College of William & Mary has worked with a pair of firms, Sonic Nets and Acoustic Lighthouse, to develop sound-based technological solutions that may have solved the problem, presented last week in Austin, Texas, at the annual meeting of the American Association for the Advancement of Science. By saving birds’ lives, the technology could reduce at least some of the popular opposition to development of such clean energy projects—a problem known as “social licence” or the willingness of citizens to support or oppose a particular project.

Both techniques use sound waves to scare away birds from wind farms or agricultural areas. These “sonic scarecrows” have been trialled and shown to disperse birds from these locations, significantly reducing their numbers. The first technique involves the broadcast of frequencies that disrupt the ability of birds to communicate with each other, thus frightening them away. The second, specific to wind farms, involves the mounting of a directional speaker on a turbine that emits bursts of sound. As birds in flight—with their eyes situated on either side of their head—do not focus forward, they can fail to notice such narrow structures, risking collision. Turbines also kill about 50,000 bats each year in Canada, but the sonic scarecrow technique has yet to be assessed with respect to these mammals.

PICS 2060 Project researcher James Donald is currently exploring the challenges that clean energy projects face from social licence. He has come across the concerns of birdwatchers, both as a scholar and a former wind-energy sector worker.

“There are undoubtedly issues, but the severity depends on the location of the wind farm, what types of bird species are present in the area, as some are more prone to being killed than others, and interference with migratory routes used by certain species,” he says. “The issue is most severe when ‘at risk’ bird species are affected.”

He notes that similar types of technology have been used to scare other animals away from places where they might be at risk. However, these can also be controversial as the work is akin to habitat loss, which may have just as great an effect as the wind turbines on mortality.

“Sensitive project siting to avoid areas of bird habitat and migratory routes is probably the first option in Canada to get over this issue,” he argues.

“All that said, I always like to remember that the number of birds killed by wind turbines is dwarfed by the number killed by pet cats!”​

In depth



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