April 15, 2011
British Columbia

Birds versus blades

By Allan Wishart - Prince George Free Press, www.bclocalnews.com 14 April 2011By Allan Wishart - Prince George Free Press, www.bclocalnews.com 14 April 2011

It’s not usually a good result for the animal, UNBC instructor Ken Otter told a Cafe Scientifique audience at Cafe Voltaire on Wednesday evening.

Otter, an instructor in the ecosystem science and management program, said people have been researching the idea that wind farms and birds have a collision problem.

“Most research suggests the problem is not much worse than with other tall structures, such as high-rise buildings or radio towers,” he said in an interview with the Free Press, “but certain species seem at a higher risk.”

Most of the at-risk species are migratory birds, which may encounter the turbines on their regular route, and “soaring” birds.

“These are species which make use of a lot of updrafts when they’re flying, birds like hawks or eagles and cranes.”

With the wind-farm technology still relatively new in canada, the opportunity is there to work with industry to make it as safe as possible for the animals, he said.

“What we’re finding s it doesn’t take much to make the farms safer for birds. A lot of it is looking at weather patterns.”

Generally, he said, the birds are flying at elevations well above the turbines. Sometimes, however, a weather pattern will push them lower, to where they may be at risk.

“We can plot out the tracks of their migrations and see how they use the ridges and rises. That allows us to predict where the patterns will occur, and we can get very specific information.”

How specific? Otter says in some cases it could be a question of just idling one turbine in a group for a few minutes to allow a flock of birds to get by.

“Most of the turbines can be idled in about two minutes. It might just be a question of having someone out there to keep an eye on the conditions and, if needed, call back to the main operation and ask them to shut one of the turbines down for a few minutes.”

Otter said a University of Calgary study found bats ran into a different problem when it came to wind turbines.

“They have very thin walls in their lungs, and a lot of capillaries to distribute the blood. the study found groups of sometimes hundreds of bats dead near a turbine, but with no contusions on their body to indicate they had been hit by one of the vanes.”

Autopsies showed the capillaries had burst inside the bats. This led researchers to take a look at how the turbines affected wind pressure in their area.

“What happens with any fan is there is a low-pressure area created right behind the vanes. The bats were coming into this area, and their capillaries were bursting because of the sudden drop in pressure.”

Again, the solution may be as simple as varying the speed the vanes turn at to ease the drop in pressure.

“We’re working with them, showing them how these small changes can keep the birds and bats safe, and they’re listening.”