Most birds migrate much higher than the deadly tips of wind turbine blades. It’s during takeoff and landing when they face the biggest perils, said Wendy Estes-Zumpf, zoologist with the Wyoming Natural Diversity Database.
Zoologists, ecologists and mapping specialists from the diversity database and The Nature Conservancy recently finished the first statewide report that tries to predict where birds migrate – and more importantly where they stop to rest. They hope it will ultimately help land managers and developers understand where wind turbines would be the least destructive.
Wyoming’s topography is complex, which makes predicting where birds migrate and stop difficult, Estes-Zumpf said.
“We weren’t focused so much on species-specific impacts,” she said. “What we were trying to do was find groups of species that migrate across the state in order to minimize impacts.”
About 15 percent of Wyoming has or could have high wind energy development. Of that area, about 73 percent is in high migration stopover points, said Estes-Zumpf.
Scientists already know how deadly turbines can be if placed in the wrong areas. Wind turbines may kill more than 570,000 birds each year, according to an estimate published earlier this year in a peer-reviewed study in the Wildlife Society Bulletin.
What scientists didn’t have until now was a comprehensive look at where birds are predicated to stop and rest across the state.
The group focused on four types of birds
that represent a chunk of Wyoming’s migrating avian species: wetland, riparian and sparse grassland birds and raptors. Each one includes sensitive species tracked by the diversity database, a research arm of the University of Wyoming.
“The sparse grassland group is the one where habitat is very important,” she said. “It is also in those eastern plains where there is a big push for wind energy development, and we know very little about the species.”
High plains birds such as the mountain plover don’t concentrate in big groups around water like geese or ducks, which makes it more difficult to track, she said.
Estes-Zumpf and Amy Pocewicz, a landscape ecologist with The Nature Conservancy, collected all information they could find on bird habits, and used the information to create the model.
Wetland birds, for example, tend to follow streams and rivers when they migrate. They also like to stop in areas with larger bodies of water such as lakes and reservoirs, especially if the water is near a type of grain field.
Because raptors don’t stop in predictable places like the other birds, the group tried mapping their entire migration patterns, Estes-Zumpf said.
The group then sent the model to 20 regional experts on bird migration to verify if the experts had seen or knew of birds moved through certain areas, she said.
A separate study started recently to test the model on the ground and results are pending.
It is too soon to say what type of practical impact the maps will have since it was released earlier this month.
PacifiCorp, a regional energy company with wind turbines in Wyoming, doesn’t have plans for more turbines in Wyoming. If it did, the company would consider using a bird migration map, said Jeff Hymas, PacifiCorp spokesman.
The Chokecherry and Sierra Madre Wind Energy Project in southeast Wyoming is poised to be the largest wind development in North America and has already gathered site specific information for its turbines, said Kara Choquette, spokeswoman for Power Company of Wyoming, the company building the project.
“We can’t speculate on whether other potential wind developers may or may not find these generally modeled maps to be helpful for their efforts,” she wrote in an email to the Star-Tribune.
The maps aren’t intended to replace site-specific planning, said Pocewicz. But they can give land managers and developers a place to start in the planning process.
There’s still work to be done and more data to collect, said Estes-Zumpf. This essentially gives land managers and developers a road map that didn’t exist before. As people learn more about where birds migrate and stop, they can add to the existing framework.
“We’re hoping people will look at these maps and say, ‘This area isn’t listed as important and I know they are there,’” she said. “This is a stepping off point to try and obtain better data and revise the maps and make them better.”