Already under siege by a fatal disease called white nose syndrome, North American bats have another enemy: wind turbines.
A researcher affiliated with the University of Colorado estimates that more than 600,000 bats were killed by wind turbines in 2012. Writing in the journal BioScience, Mark Hayes cites earlier studies, which estimated that as many as 888,000 bats would be killed each year, before settling on his own number.
Hayes used estimates from 21 locations in the contiguous U.S. for his statistical analysis. The highest rate of bat fatalities, which Hayes describes as fatalities per megawatt per year, occurred at Buffalo Mountain, Tennessee. Some wind sites in the West recorded very low numbers.
“This estimate of bat fatalities in 2012 is probably conservative,” Hayes writes.
But Hayes says there’s still lots to learn about the problem. There’s a lack of reliable information about bat populations around the country because of their small size and nocturnal habits, he writes.
“This lack of reliable population estimates makes conservation and management planning challenging, especially in the face of other recently emerged threats to North American bat populations, such as diseases and a changing climate,” he says.
Given the ecological and economic benefits of these small mammals, Hayes recommended more research.
New hope for raptors
Government researchers have estimated that wind farms also are responsible for the deaths of dozens of bald and golden eagles. But the Associated Press reports that a combination of technology and trained spotters have helped avert fatal collisions at a large wind farm in the West.
Technicians in California are able to shut down wind turbines in Montana 1200 miles away in less than 30 seconds when the flight patterns of golden eagles and other raptors threaten a collision, the AP reported.
Tracking radar, cameras and trained spotters at the Rim Rock Wind Facility in Montana are so far proving effective in averting collisions between the birds and turbine blades. The 189-megawatt wind farm has 126 turbines, making it the states’s largest wind facility.
The wind farm’s owner says its three-tiered approach has the best chance of success in averting bird strikes.