New Study Helps Wind Industry, Wildlife Managers Identify Risks to Certain Raptors from Collisions with Wind Turbines

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A recent U.S. Geological Survey (USGS) and Oklahoma State University study shows not all raptor species are equally impacted by collisions with wind turbines. Of 14 species studied, five are at risk of population declines due to collisions.

“While our work does not show that wind energy development will drive these birds to extinction or even put them at risk of becoming endangered, instead it helps the wind industry and wildlife managers direct attention to those in greatest need when it comes to preventing and mitigating  collisions with turbine blades,” said USGS research ecologist Jay Diffendorfer, who led the study.

Of the raptors evaluated, barn owls, ferruginous hawks, golden eagles, American kestrels and red-tailed hawks had the highest potential for population-level impacts. None of these species is currently endangered or threatened, but barn owls, ferruginous hawks, golden eagles and American kestrel populations are already in decline for reasons other than wind energy development.

Conversely, the burrowing owl, Cooper’s hawk, great horned owl, northern harrier, osprey and turkey vulture showed low potential impacts from both current and forecasted wind energy development. Three other species, the merlin, the prairie falcon and the Swainson’s hawk, could not be conclusively categorized for risk.

Scientists used existing fatality data on collisions with wind turbines to project population structures of each raptor species and future fatalities from the current national capacity of around 100 gigawatts to about 240 gigawatts.

The 14 species of raptor chosen for the study had sufficient population information available to allow the modeling. Raptors live longer than most birds, take longer to reach adulthood and have fewer offspring, making these populations more reliant on adults surviving for longer periods and the impact of wind turbines greater on the population.

Wind energy made up about 3% of the energy consumed in the United States in 2020, according to the U.S. Energy Information Administration, and more and larger wind turbines are added every year. In addition, more support infrastructure, including roads and maintenance facilities, will be required. As more efforts are made to reduce carbon emissions and increase renewable energy production, wind energy development and its requirements are likely to continue to grow.

“With more wind turbines, there will be a greater need to mitigate impacts from energy production on wildlife species,” observed Diffendorfer. “This paper provides an initial attempt to prioritize species for which mitigation may be most influential.”

To expand wind energy in the U.S. while minimizing impacts to wildlife, resource managers need a better understanding of how wildlife fatalities at wind facilities affect species populations. The USGS has a broad, integrated research program focused on energy-environment issues, including wind energy impacts on wildlife. The study is part of a broader effort across USGS to better understand the effects of collision fatalities on bird and bat populations.

The article is entitled “Demographic and potential biological removal models identify raptor species sensitive to current and future wind energy” and is published in Ecosphere. It can be accessed here.