The western meadowlark isn’t heard much around wind turbines, but not because of the whirr of the churning blades in the wind.
A 10-year study of nine grassland bird species in North and South Dakota finds that wind turbines can displace meadowlarks and other grassland birds away from the turbines for years.
The study’s findings were released Tuesday by the Jamestown-based Northern Prairie Wildlife Research Center of the U.S. Geological Survey.
The meadowlark – the state bird and a species of concern – has declined in population by nearly half since the late ‘60s at an annual rate of 1.23 percent, according to the USGS.
Jill Shaffer, one of the study authors, said the research is valuable because, starting in 2003, it documents the birds’ presence before and after the turbines were constructed.
It’s also the longest duration study of its type ever done, she said.
Generally, the findings weren’t good news for most of these sensitive species.
“New wind energy in prime wildlife habitat can influence the distribution of grassland birds for years after construction, including species whose populations are in serious decline,” the report concludes.
Seven of the nine species, including the meadowlark and the bobolink, were displaced from good breeding habitat for the study’s duration.
The killdeer was temporarily attracted to the turbine gravel pads and roads for nesting and the vesper sparrow species didn’t react either way.
The study looked at three wind turbine sites – two in North Dakota in Oliver County and Forbes and one at Highmore, S.D.
The sites were selected because of their location in prairie grasslands and because their locations were shared ahead of time by wind developers to allow a before and after comparison, Shaffer said.
NextEra Energy helped sponsor the study and owns the Oliver County and Highmore projects. The company didn’t provide comment for this story.
In the intervening decade, wind energy in North Dakota now exceeds 1,000 turbines that produce more than 2,000 megawatts of electricity, according to information from the Public Service Commission.
“We got together with NextEra and the U.S. Fish and Wildlife Service before turbines were even built in North Dakota out of concern for the impact they would have. We wanted to have a quality study of long duration on the birds before, during and after construction,” she said.
There is no one-size-fits-all conclusion about the birds; not all the birds studied generated the same results in all three of the locations, according to Shaffer.
The meadowlark exhibited sustained avoidance only at the South Dakota wind farm – meaning it showed up in very small numbers within a half-mile five years after construction. That’s likely because there were more human-caused disturbances, such as more roads, cell towers, land conversion and other factors than the other two sites, she said.
“Meadowlarks are fairly tolerant of human activity, but they do reach their tolerance threshold,” Shaffer said.
The grasshopper sparrow, a bird that’s significantly declining, was the only species that showed avoidance at all three locations, she said.
She described the field methodology as very intense, with grids laid out one-half mile in all directions from the turbines studiously walked and charted by the technicians.
The list of birds studied included western meadowlark, grasshopper sparrow, bobolink, upland sandpiper, clay-colored sparrow, chestnut-collared longspur, savannah sparrow, killdeer and vesper sparrow.
The agency doesn’t evaluate the suitability of wind development but makes information available for regulators, wind companies and natural resource managers, Shaffer said.
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