Bats hang out at wind farms?
Ground-breaking research is underway across Western Canada into how wind turbines affect migratory bats, and how to save the furry mammals from being hurt as they fly around the Prairies.
This week, a University of Calgary research team revealed that many dead bats found at a wind farm in Pincher Creek, Alta., had severe internal injuries consistent with a sudden drop in air pressure near wind turbine blades.
One of the authors of the study said the bats, which usually fly south from the Prairies from mid-July to mid-September, could be saved by controlling when the turbine blades rotate during bat migration.
The migratory bats usually travel when wind speeds are low, so operating turbines during the migration period only when there’s a higher wind speed might help.
“It’s an issue around the globe… . You can see it right around the world, and right across the Prairie provinces,” said Erin Baerwald, a University of Calgary graduate student who led the research published in the online edition of the journal Current Biology.
She said the lungs of migratory bats can be damaged when outside pressure drops, causing their capillaries to burst. The tissue damage can be fatal.
There are nine species of bats in Alberta, but not all are migratory. Baerwald said researchers examined the carcasses of three species of bats found near the turbines: hoary bats, silver-haired bats and eastern red bats.
She thinks the study indicates wind turbines pose “some risk” for migratory bat populations, which are difficult to track and count.
“We don’t know what kind of effect this has on population sizes.”
Meanwhile, University of Winnipeg biology assistant professor Craig Willis is leading students on other bat studies related to wind turbines.
One recently launched three-year study supported by Manitoba Conservation’s Sustainable Development Innovations Fund will look at three species of migratory bats that fly through the province’s landmark wind farm of 63 turbines near St. Leon, about 150 kilometres southwest of Winnipeg.
“(We’re) trying to understand if bats are attracted to wind turbines. Second, what’s the reason for that … and third, can we predict when mortality events happen,” Willis said. “We know that this is a worldwide phenomenon. It’s not just happening in Alberta. It’s not just happening in the eastern United States. It’s not just happening in Manitoba. It happens at wind farms all over the place, but there is variation between sites. Some sites have higher (death) rates than other sites… . We’re still not completely sure why we’re finding all those bats in those specific places.”
In April, Manitoba Hydro announced it was in final negotiations about the province’s second wind farm, near St. Joseph, where as many as 189 turbines would add enough electricity to Manitoba’s grid to power 100,000 homes.
Willis’s study, to be completed by 2010, will examine whether bats are actively attracted to wind turbines and other tall structures during the migration season. Researchers will use detectors to measure bat traffic around the turbines, as well as studying bat carcasses for mating activity. Willis hypothesized the creatures might be attracted to tall structures for mating purposes.
“Otherwise, they can’t find each other to mate,” he said.
Willis said tracking migratory bats is difficult, but worthwhile because they contribute a lot.
“Bats do tons of stuff for us for free. That little brown bat that’s flying around can eat tons and tons of insects each night… . We save money on pesticides, we save money on crop losses, bats are also spreading nutrients around as they fly from place to place.”
Manitoba bat blitz
Researcher Craig Willis and his students are seeking bat roosts around the province and in northwestern Ontario so they can implant the mammals with tiny microchips. The researchers want to find out in which caves the mammals hibernate .
If you have bats in your home or cottage, or know a building or forest where they hang around, please contact the researchers at 330-1756 or t.parkinson-ra@uwinnipeg.ca
27 August 2008
Tags: Wind power, Wind energy
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