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Game and Fish looks at alleviating challenges for mule deer populations

by Wyoming Livestock Roundup

Over the last 20 years, mule deer populations in the state of Wyoming have declined significantly, says Wyoming Game and Fish Department (WGFD) Chief Game Warden Brian Nesvik. 

“We have seen declines of 25 percent or more statewide,” Nesvik comments. “There are a lot of folks across the state who are concerned.”

Between hunters, landowners and wildlife conservationists, many Wyoming citizens continue to look at mule deer populations, and Nesvik notes that WGFD is working hard to identify actions to help the populations.


“When we look at the causes of mule deer population reduction, we see greatly declining fawn recruitment,” Nesvik explains. 

In the mid-1980s, fawn recruitment numbers were in the 80s, meaning 80 fawns per 100 does were still alive following hunting seasons – significantly increasing their likelihood of survival over the long-term. 

“Now, our statewide average is below 65 fawns,” he says. “We have a lot of areas of the state that are significantly below those numbers.”

Nesvik adds that a recruitment level of 65 fawns per 100 does is scientifically determined to be a sustainable level. 


When looking at the causes of mule deer population decline, Nesvik marks two major considerations – where mule deer live and how they live.

“These are equally important components of the problem,” he notes. 

When looking at where the mule deer live, Nesvik says that the drier climate that habitats are experiencing causes a decrease in productivity and nutritional quality. 

Habitat concerns

“Mule deer spend their time eating brush-type species,” he explains. “They aren’t grass eaters. Rather, they consume sagebrush, mountain mahogany, forbs and similar plants.”

Because those habitats that support mule deer are old and not as productive as newer habitats, they are able to support fewer animals. 

“There are a whole variety of reasons that affect the habitat side of the equation,” says Nesvik. “Drought is a factor, and in some cases, we’ve suppressed fire to the point that brush species are old and not as productive.”

Comparing mule deer habitats to a cow/calf operation, Nesvik says, “On a ranch with a set amount of ground, if a rancher is going to get bigger, the only way to have more cows is to produce more grass.”

Methods of improvement include fertilization and removal of sagebrush, for example. 

“Essentially, the only way he can run more cows is if they get water and he sees an increase in grass production,” Nesvik says. “We are in the same boat with mule deer.”


The WGFD works to actively improve habitats by implementing large-scale habitat enhancements. 

“We have worked to improve habitats, specifically in places where mule deer are spending their time during critical times of the year,” Nesvik comments, “and we continue to look for places we can do habitat work on a larger scale.” 

In the Wyoming Range and the Platte Valley, to a larger extent, private landowners have been pivotal in providing places, funding and ideas for habitat improvement projects.

How they live

Because mule deer face the same challenges that other species face – such as disease, predators and highway collisions – the population sees decreases each year.

“One of the things that exacerbates habitat problems are predators, because they work symbiotically with the degraded habitat,” Nesvik says. “Literature suggests that predators can have more of an impact on populations of mule deer when habitats are of lower quality.”

Better habitat may help deer to survive and withstand predator influences.

“It is a double whammy for them,” Nesvik says. “We have mule deer in the West that travel 100 miles from the summer to winter ranges, and they have to have good groceries along the way.”

Highway collisions

Nesvik also noted that highway collisions also can have impacts on deer populations.

“We have some issues with migration corridors,” he says. “While migrating, they have to be able to get across the highway.”

Large-scale projects around Baggs, Cokeville and Daniel have been put in place to install underpasses along highways for deer to utilize.

Other deer concerns

To alleviate predator concerns, Nesvik says WGFD is also working with the Animal Damage Management Board (ADMB) to address potential predator effects.

“We have looked at areas of the state where ADMB and local Predator Management Boards are going to do predator control projects for livestock anyway,” he explains. “We’ve worked with ADMB to work on predator management projects that benefit both livestock and mule deer fawning areas.”

WGFD has also worked to address mountain lion quotas to alleviate predation concerns. 

Overall, WGFD continues to seek ways to aid declining mule deer populations and help the species to recover in Wyoming.

Saige Albert is managing editor of the Wyoming Livestock Roundup and can be reached at

Good news story

While mule deer populations are declining, Wyoming Game and Fish Department (WGFD) Chief Game Warden Brian Nesvik sees successes in elk numbers across the state.

“While we don’t have our final numbers in yet, it looks like we will have a second year in a row of record harvest,” he says. “That is a result of significant efforts from many across Wyoming.”

Nesvik notes that the WGFD has undertaken several efforts to improve elk harvest though out the state, but he recognizes that landowner participation and cooperation has resulted is key to success.

“We have learned in a big way that when we can work with private landowners, hunters can kill elk,” he says. “That has been a huge part of our success.”

Efforts like the Hunter Management and Assistance Program in Meeteetse and on Iron Mountain have helped to put WGFD employees on the ground with hunters to increase harvest.

“We have also been helped by the Wyoming Legislature, where provisions were approved so people could get up to three elk licenses,” he says.

“We have liberalized many seasons, increased license allocation, worked with landowners and increased our cow harvest across the state,” Nesvik comments. “There is more good news to follow with elk numbers.”


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