Purchase photos

Study refutes wind tower effect on greater prairie chickens

7/12/2013

By MIKE CORN

mcorn@dailynews.net

MANHATTAN -- A new five-year study debunks a litany of previous research showing wind power development adversely affects prairie chickens.

The study was conducted by Kansas State University wildlife biologist Brett Sandercock, who looked at the effect a Concordia wind farm had on greater prairie chickens.

"Greater prairie chickens were not strongly affected by wind power development in Kansas," the study states.

It's the first study that contradicts a series of earlier studies showing prairie chickens generally avoided tall structures, such as wind turbines and power lines.

While most of the studies detailing avoidance focused on lesser prairie chickens, some found the same results for greater prairie chickens.

Lesser prairie chickens, for example, are known to avoid nesting or rearing chicks within a quarter mile of power lines and even a third of a mile from roads.

In Sandercock's study, there was, however, a negative impact on lek persistence near the turbines, and females avoided the structures during the breeding season.

The study, released Wednesday, found "no impacts on wind power development on nest site selection, female reproductive effort or nesting success or population numbers," the study reports. "Positive impacts of wind power development included an increase in female survival rates. We hypothesized that the unexpected increase in female survival was related to changes in trophic interactions and disruption of the foraging behavior of raptors that kill prairie chickens at lek sites."

Researchers also found conservation management practices seem to have the strongest effect on the birds, Sandercock said. Because prairie chickens are ground-nesting birds and need adequate cover for their nests to survive, grazing and fire management practices can affect how much nesting cover is available for chickens.

"A lot of what drives nest survival is the local conditions around the nest," Sandercock said in a release. "Do they have good nesting cover or not? Our results are important because they suggest ways for mitigation."

Results from the study were surprising, according to a news release from the university, especially because similar studies have shown that oil and gas development affects prairie chickens, Sandercock said. With wind power development, the researchers had the unexpected result of female survival rates increasing after wind turbines were installed, potentially because wind turbines might keep predators away from nest sites. Female mortality rates are highest during the breeding season because females are more focused on protecting clutches than avoiding predators, Sandercock said.

"What's quite typical for these birds is most of the demographic losses are driven by predation," Sandercock said. "We can say that with confidence. What's a little unclear from our results is whether that increase in female survivorship was due to the effects of wind turbines on predators."

The study was paid for from a mix of wind energy and conservation groups.