The research represents one of the first tallies of eagle deaths attributed to the nation's growing wind energy industry, which has been a pillar of President Barack Obama's plans to reduce the pollution blamed for global warming. Wind power releases no air pollution.
But at a minimum, the scientists wrote, wind farms in 10 states have killed at least 85 eagles since 1997, with most deaths occurring between 2008 and 2012, as the industry was greatly expanding. Most deaths -- 79 -- were golden eagles that struck wind turbines. One of the eagles counted in the study was electrocuted by a power line.
The vice president of the American Bird Conservancy, Mike Parr, said the tally was "an alarming and concerning finding."
A trade group, the American Wind Energy Association, said the figure was much lower than other causes of eagle deaths. The group said it was working with the government and conservation groups to find ways to reduce eagle casualties.
Still, the scientists said their figure is likely to be "substantially" underestimated, since companies report eagle deaths voluntarily and only a fraction of those included in their total were found during searches for dead birds by wind-energy companies. The study also excluded the deadliest place in the country for eagles, a cluster of wind farms in a northern California area known as Altamont Pass. Wind farms built there decades ago kill more than 60 per year.
The research affirms an AP investigation in May, which revealed dozens of eagle deaths from wind energy facilities and described how the Obama administration was failing to fine or prosecute wind energy companies, even though each death is a violation of federal law.
The U.S. Fish and Wildlife Service, which employs the six researchers, has said it is investigating 18 bird-death cases involving wind-power facilities, and seven have been referred to the Justice Department. The authors noted the study's findings do not necessarily reflect the views of the agency, although some of their data was obtained from staff.
Wind farms are clusters of turbines as tall as 30-story buildings, with spinning rotors as wide as a passenger jet's wingspan. Though the blades appear to move slowly, they can reach speeds up to 170 mph at the tips, creating tornado-like vortexes.
Wind farms in two states, California and Wyoming, were responsible for 58 deaths, followed by facilities in Oregon, New Mexico, Colorado, Washington, Utah, Texas, Maryland and Iowa.
In all, 32 facilities were implicated. One in Wyoming was responsible for a dozen golden eagle deaths, the most at a single facility.
The research was published in the Journal of Raptor Research.
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