Killing Them Softly: How Wind Turbines Affect Waterfowl Nesting
June 10, 2013
Green energy may be good for the environment, but a growing number of scientists are concerned it may not be for waterfowl. A recent study in the Dakotas is adding fuel to those concerns. It found breeding duck densities were considerably lower around large-scale wind farms compared to wetlands with no turbines in sight.
"We don't know if the decline is a result of the towers themselves, the motion, noise of the blades, or the increased traffic from maintenance workers," says USFWS biologist Dr. Chuck Loesch.
"It could be a combination of all those or something else, but that really wasn't the focus of the study. We wanted to determine if the presence of wind energy development had an impact on duck breeding densities."
One nesting site had a 56-percent lower breeding pair density than a similar site with no wind turbines. Overall, the number of breeding ducks using wetlands near the wind farms was 20 percent lower than in wetlands with no wind development nearby.
Ducks are avoiding wind projects, but they may not have many options in the future. Loesch says the push for renewable energy will likely lead to a huge number of large-scale projects in the wind-rich Prairie Pothole Region. The projected footprint of future wind farms will cover more than 15,000-square miles by 2030 if the federal government meets its goal. The Department of Energy wants 20 percent of the country's energy to come from renewable sources. It's impossible to say where those new turbines will pop up, but Loesch says it's inevitable many will be near critical areas.
"We are losing quality wetlands in the Prairie Pothole Region at an alarming rate already," he says. "Wind energy might have a compound effect."
Another study determined windmills don't kill many breeding female ducks. Tanner Gue, a Ducks Unlimited conservation specialist, fitted radio transmitters on 77 hen mallards and 88 female blue-winged teal near a large wind energy project on the North Dakota-South Dakota border in 2009 and 2010 to determine mortality rates near a wind farm.
"Females get involved in some pretty territorial courtship flights and we hypothesized that they tend to be less aware of their surroundings during this period. Basically, we wanted to know if they were vulnerable to flying into the path of a turbine blade," says Gue. "Because female survival during the breeding season is a strong population driver, we focused on females."
Of the 165 birds marked, just one mallard died after being struck by a blade. Gue and fellow researchers also monitored 145 teal and mallards on a nearby site that did not have windmills.
"We wanted to compare overall mortality rates to see if wind development might lead to higher rates of predation. It turned out mortality rates were pretty similar," he says. "That wasn't the primary focus of our study though, and I think it's something that warrants further research. Predation can increase when habitat is fragmented, but we don't know how wind energy plays into that."
Researchers don't know the long-term impact on waterfowl staging and feeding areas and migratory paths, either. That's why Long Point Waterfowl executive director Dr. Scott Petrie is frustrated with the lack of cooperation from wind energy companies. He works on the Canadian side of lakes Ontario, Erie and St. Clair, an important staging and wintering region for waterfowl in the midst of a wind energy boom.
An outspoken critic of the poorly-regulated rush to build towers, Petrie thinks the Ontario government and private companies need to step back and evaluate the potential effects of wind projects. Ontario has lost upwards of 85 percent of its coastal wetlands and is at risk of losing more. Right now, 2 percent of the province's energy comes from wind. However, a push by the provincial government aims to increase the output to 20 percent. The best wind resources are located along the marshes and farmland adjacent to the Great Lakes, the same areas used by migrating waterfowl.
"There are 4,000-6,000 turbines planned for onshore development and thousands more could be built offshore in the near future," says Petrie. "One proposed offshore project will have as many as 800 turbines. Those offshore turbines will be placed in shallow water, which is diving duck habitat."
Petrie doesn't know for sure how significant the overall impact of large-scale wind development will be, but doesn't want to find out after it's too late.
"Putting up a wind tower next to a marsh is like putting up a skyscraper next to a marsh," he says, adding a number of studies have examined the impact of tall structures like drilling rigs and cell towers on other types of wildlife. Sage grouse, for instance, will abandon favored breeding and nesting areas when tall structures are erected nearby. Waterfowl will shy away from wind turbines, especially those built in the middle of important feeding areas like coastal agricultural fields.
"We just need to evaluate all the consequences before we rush in," he said.
Petrie jokes that many energy companies, "have my picture on a dart board." He initially managed to convince one wind developer to move a project away from an important wetland, but has been unable to convince others to avoid sensitive areas.
Loesch is more optimistic. He says energy companies do seem willing to at least listen to wildlife biologists, even though they aren't required to follow any siting guidelines. The groundbreaking study he was involved in was actually funded in part by an alternative energy company, which funded other studies that examined the impact of wind energy, as well.
"I do believe many of these companies are interested in understanding the impacts," he says.
With such a frantic push to "go green," showing concern may not be enough to prevent or reduce the impact of so many large wind projects.