Wind Farms Hazardous To Nearby Bats
Wind farms may add risk of death to nearby bat populations due to the change in air pressure that can kill the mammals, Canadian researchers said.
By studying dead bats found near a wind farm, scientists concluded that their injuries were consistent with sudden loss of air pressure.
Bats use echo-location to navigate. However, when trying to avoid the swinging blades, they are unable to detect the pressure changes near the turbines, thus causing them to collide with the blades, resulting in death.
"An atmospheric pressure drop at wind turbine blades is an undetectable – and potentially unforseeable – hazard for bats, thus partially explaining the large number of bat fatalities at these specific structures," said Erin Baerwald, who led the research team at the University of Calgary.
Bat deaths around wind farms have been widely documented across Europe and North America.
Earlier this year, a bid to build a wind farm near Bideford in north Devon was turned down because of the potential impact on the mammals.
However, further insight in to the cause of the bat deaths was lacking until the Calgary team released their report.
The team collected carcasses of hoary and silver-haired bats killed at a wind farm in south-western Alberta.
Examinations showed that fewer than half had external injuries that could have been caused by collision.
But about 90% had internal hemorrhaging, most notably in the chest cavity, a condition that puts pressure on the lung and can be fatal.
A bat flying into the low-pressure zone finds its lungs suddenly expanding, bursting capillaries in the surrounding tissue, which then becomes flooded with blood.
Birds do not experience the same dangers because they have more rigid lungs, scientists said.
"Given that bats are far more susceptible to barotrauma than birds, and that bat fatalities at wind turbines far outnumber bird fatalities at most sites, wildlife fatalities at wind turbines are now a bat issue, not a bird issue," said Ms Baerwald.
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