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New studies show pronghorn avoid wind turbines. But more work is being done to determine the exact toll and wind development expands.

Big game, in general, don’t like being around humans.

Sure, we all see mule deer in our rose gardens, moose under apple trees and pronghorn gathered on golf courses, but the bulk of Wyoming’s ungulates would rather not be around people or their moving vehicles.

Determining just how much big game avoid human infrastructure – oil and gas wells, wind turbines, roads and highways – is another story.

It’s a question University of Wyoming professor Jeffrey Beck and others set out to understand in 2010 with a study of one of the world’s largest pronghorn herds living near wind turbines in Shirley Basin northwest of Laramie. The results from his three-year study, paid for by PacifiCorp, were published in early 2020, and showed that pronghorn did not, in fact, like being around wind turbines in winter.

But Beck and others could not determine the exact physical toll that aversion has on pronghorn.

So in 2018, the Wyoming Game and Fish Department, the USGS Cooperative Fish and Wildlife Unit at the University of Wyoming and Invenergy, then PacifiCorp, paid for a six-year study looking more in depth at the question of what impact wind turbines have on pronghorn, both in the winter and summer. With three years of the study done, coop director Matthew Kauffman can offer a few clues.

First, wind turbines do displace pronghorn, which in return lose valuable food especially in winter months. Second, and maybe even more importantly, more than a decade of animal tracking data shows it’s possible to site wind turbines in places that have less of an effect on Wyoming’s speedgoats in a way that still allows for wind development.

“We know there is a negative effect, and we would fully expect that to translate that animals don’t eat as much, they don’t put on as much fat, they don’t survive the winter as well and have as many young, all of those are logical,” Kauffman said. “But our methods end up being somewhat crude when we try to connect that to reduced survival or population growth. They’re small incremental changes. And that’s one of the challenges we’re trying to overcome in a six-year study.”

It’s with Beck and others’ research that groups like Wyoming Energy Forum, a newly formed organization of landowners, environmentalists and concerned citizens, is asking Wyoming to pause and consider the impacts of permitting and building some of the nation’s largest wind farms.

“What we want to do is get people to think about this more holistically,” said Dan Neal, the Wyoming Energy Forum’s acting community outreach coordinator, “and think about where these wind farms should be allowed.”

Unpredictable pronghorn

The concept that energy development harms wildlife is not new. Research published in 2017 by pioneering wildlife migration scientist Hall Sawyer pinned down an exact amount for mule deer in western Wyoming. His results were staggering. Mule deer in the area dropped by 36% as oil and gas fields developed.

“Our results indicate behavioral effects of energy development on mule deer are long term and may affect population abundance by displacing animals and thereby functionally reducing the amount of available habitat,” the study read.

But mule deer and pronghorn aren’t the same creatures, and don’t follow the same migration patterns, Kauffman said. Mule deer will winter in one location that’s often no bigger than 2 or 3 square miles, travel 100 miles over a nearly identical path as they did the year before, and summer in another, similarly-sized area. Pronghorn movements, on the other hand, are a bit more “messy”.

“They are almost more nomadic,” Kauffman said. In harsh winters they may migrate from Shirley Basin all the way to Rawlins, in more mild winters, they largely stay put.

That makes determining how they interact with turbines trickier.

Beck and others began their research in 2010 by placing 35 collars on female pronghorn before wind turbines were established on the state’s Dunlap Ranch. The next year they collared another 17. They followed those same pronghorn in the winters of 2011 and 2012 to see how the newly installed turbines effected their movements.

Kauffman, Game and Fish biologists and others are running a similar study with about 80 pronghorn collared and over the course of six years.

Shirley Basin offers plenty of pronghorn to study. The Medicine Bow herd, as it’s called by Game and Fish, had more than 43,000 animals in its 2019 count. The goal for 2020 was for more than 50,000 animals, according to Game and Fish.

That’s why so much attention has been paid to these particular creatures, and as wind development continues across the West, why researchers, environmental groups and states are interested.

Developing a balance

As state revenues from oil, gas and coal are plummeting, and pressure for renewables is increasing, now is the time Wyoming needs to consider impacts on wildlife and natural spaces, Neal said.

“Everyone knows the impact of climate change, it will kill a lot of birds and animals,” Neal said. “But that doesn’t mean we should throw up our hands and say ‘ok, anybody who wants to come here and throw up a turbine let’s do it.’”

Plans continue for more wind development across the southeastern part of the state, from the Chokecherry and Sierra Madre Wind Energy Project between Rawlins and Saratoga to the controversial Rail Tie project south of Laramie.

A 2016 study using some of the data from 2010-2012 showed that wind turbines had not impacted pronghorn survival rates. But Beck said it’s possible that was simply a matter of scale – as Shirley Basin becomes more developed, impacts could increase.

The studies have also identified crucial pronghorn winter range and migration routes, which could help developers understand where turbines will have the least impact on pronghorn longevity.

“That’s the wisdom of a mapped corridor,” Kauffman said. “We can say these are the places that animals need to move.”