The U.S. Fish and Wildlife Service recently released new guidelines that aim to limit destruction of wildlife habitat when new wind farms are built.
But scientists still don't know much about the long-term effects of wind turbines on wildlife. So researchers are studying a variety of bird species to determine if they are killed by spinning turbines, or avoid habitat hear them.
One of the places they're searching for answers is the prairie pothole region of North Dakota, often called the nation's duck factory.
That's where on a cool, drizzly morning, Tanner Gue recently began another long day trapping ducks.
Gue, a graduate student at the University of North Dakota, is studying how ducks and wind turbines interact on the Missouri Coteau, a remote area of rolling hills and thousands of wetlands.
It's a perfect home for ducks and a prime wind energy location.
Wind turbines built on the hilltops tower over wetlands that surround them.
"The U.S. Fish and Wildlife has put a lot of years and a lot of effort into securing lands and maintaining habitat suitable for nesting ducks so we can keep the duck factory the duck factory," Gue said. "Now these towers are a new feature on the landscape. That's why people are going 'What's going on here? Is this really a good thing?"
Gue uses ducks territorial instinct to catch them. Cage traps are set out with tame mallard hens inside. The hope is a wild hen will try to chase away the intruder and be caught in the cage. Gue wants to track hens so he can see if they nest near wind turbines.
After releasing several male ducks that wandered into the traps looking for love, Gue gets lucky.
He spots a mallard hen in one of the traps on the edge of a wetland a couple of hundred feet from the road.
Gue packs a radio transmitter in a small plastic toolbox and sprints down the hill to the trap. He wants to grab the hen quickly so she won't hurt herself trying to escape. The bird is weighed and measured. While another researcher holds the hen, Gue plucks the feathers from small spot on her back and sutures a tiny radio transmitter to the skin.
"That's it, make sure she's okay before we let her go," he said. "Then we start tracking her tomorrow, collecting data."
The entire procedure takes 15 minutes.
This duck will be tracked every day. Researchers will know where she nests and if she's killed they'll know what happened.
One question Gue hopes to answer is whether ducks will be killed flying into the turbine blades.
The second, perhaps more important question is are ducks avoiding wetlands near wind turbines.
It's only the second year for this research project and it will be at least another year before Gue will have enough data to start answering the questions.
His conclusions will be important to conservationists, hunters and the wind industry. The research is paid for by Ducks Unlimited, the U.S. Fish and Wildlife Service and Next Era Energy, a Florida-based company with hundreds of wind turbines in the upper Midwest.
Researchers are also studying several species of grassland songbirds that use this prairie wetland complex.
Like many prairie songbirds, the grasshopper sparrow population is declining because much of its habitat has been destroyed.
Ecologist Jill Shaffer of the Northern Prairie Wildlife Research Center in Jamestown, N.D., said the grasshopper sparrow is clearly avoiding habitat near wind turbines at several wind farms being studied.
"We are noticing this avoidance and the avoidance is occurring out to about 200 meters which is about an eighth of a mile," Shaffer said. "They don't like that area within 200 meters and they won't be there anymore. And yes that does diminish the quality of that habitat for them."
On the other hand, another bird, the killdeer, seems to be attracted to wind turbines because it nests in bare gravelly sites, like the gravel pads around wind turbines, Shaffer said.
Her study will continue for several years.
Kulm, N.D.-area Fish and Wildlife Refuge Manager Mick Erickson said collecting good scientific data takes several years. He said there's not enough research on the interaction between wildlife and wind turbines.
"In my opinion we are way behind the curve," Erickson said. "The wind industry, they are planning many, many turbines, wind farms, transmission corridors. On the conservation side, we're struggling to catch up."
There are plans to erect thousands of wind turbines across the upper Midwest.
Erickson said conservationists face an uphill battle to preserve privately-owned prairie and wetlands in prime wind energy areas like the Missouri Coteau.
"The monies that landowners receive from wind companies for the opportunity to place turbines on their land far exceeds what we pay for conservations easements," he said. "We're competing for the same land. If we can't compete financially, we have a tough battle to preserve that land."
Conservation groups hope voluntary federal guidelines will help protect the most valuable wildlife habitat.
Genevieve Thompson, executive director of the Audubon Society in the Dakotas, is part of a group of wind developers and conservationists working to come up with regional wind energy guidelines. She said everyone needs to give a little to make green energy work.
"Life is tradeoffs. There's no perfect solution, especially at this point," Thompson said. "But what I think everyone is working on is a system of prioritization. Where are the regions where the habitat is incredible, or unfragmented or truly unique? Where are the areas where it's already disturbed? Let's come up with regions where it's disturbed and there's good wind resource and let's at least focus on those first."
Thompson hopes to have voluntary regional wind energy guidelines established by early next year.
Tanner Gue plans to be back catching ducks next spring and gathering more data about the interaction between wildlife and wind turbines.