Wind power does not strongly affect greater prairie chickens
"We don't have evidence for really strong effects of wind power on prairie chickens or their reproduction," Sandercock said. "We have some evidence for females avoiding the turbines, but the avoidance within the home range doesn't seem to have an impact on nest site selection or nest survival."
The results are somewhat surprising, especially because similar studies have shown that oil and gas development affect 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 may 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. We can say that with confidence," Sandercock said. "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 researchers also found that conservation management practices seem to have the strongest effect on the birds, Sandercock said. 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. "Do they have good nesting cover or not? Our results are important because they suggest ways for mitigation."
The team is conducting follow-up studies to test mitigation strategies that may improve habitat conditions for prairie chickens. They are in their third season in a field study of patch burn grazing in Chase County and how it affects prairie chickens and grassland songbirds. Patch-burn grazing involves dividing a pasture into three parts and burning a third of the pasture each year. The practice creates a rotation basis so that each third of a pasture rests for two years. Preliminary data shows that patch-burn grazing seems to provide enough cover for ground-nesting birds, Sandercock said.
Collaborators on the wind development project include Samantha Wisely, associate professor of wildlife ecology and conservation at the University of Florida; Virginia Winder, assistant professor of biology at Benedictine College; Lance McNew, 2010 doctoral graduate in biology and research wildlife biologist with the U.S. Geological Survey at the Alaska Science Center; Andrew Gregory, 2011 doctoral graduate in biology and postdoctoral scholar at Northern Arizona University; and Lyla Hunt, master's student in biology, Riverside, Calif.
The Grassland Community Collaborative Oversight Committee of the National Wind Coordinating Collaborative oversaw the research project. The project received funding from a variety of sources including the U.S. Department of Energy; the National Renewable Energy Laboratory; the Kansas Department of Wildlife, Parks, and Tourism; the National Fish and Wildlife Foundation; and The Nature Conservancy.
The final project report can be viewed at http://www.osti.gov/bridge/product.biblio.jsp?osti_id=1080446.
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