One of Wyoming’s flagship mule deer herds has lost more than half of its animals to an unusual inverted snowpack that’s still killing scores of animals well into April.

The dire situation has some hunters calling on the Wyoming Game and Fish Department to temporarily suspend hunting in some areas.  

About 30% of the does in the Wyoming Range Mule Deer Herd had died by late March, when Gov. Mark Gordon convened a town hall-style meeting in Pinedale about winter’s dire effects on ungulate populations in portions of Wyoming. At the time, biologists explained that survival rates could continue to plummet — and their warnings proved prescient. 

In the two weeks that followed, another 20% of the adult female deer in the Wyoming Range succumbed to starvation and other winter stressors, a state biologist told WyoFile on Friday. 

“As of yesterday, doe survival in the Wyoming Range was around 47%,” said Embere Hall, the Wyoming Game and Fish Department’s science, research and analytical support unit supervisor.

Bucks in the herd, last assessed at roughly 28,000 animals, were about equally depleted, with just 49% surviving. Fawns are all but gone. Just two of the 100 collared yearling deer from the Wyoming Range Herd were still alive when Hall spoke to WyoFile. 

“In the Wyoming Range, it won’t surprise me that we will lose all of the marked juveniles that we have before the winter is over,” she said. “In fact, that’s likely.” 

This dead doe deer near Kemmerer, a casualty of the winter of 2016-’17, was a member of the Wyoming Range Herd. The ongoing winter is hitting the herd harder than ever, and had killed an estimated 53% of all does through April 13. (Mike Koshmrl/WyoFile)

The mortality data is not comprehensive. It’s not like every fawn in the entire herd will die, Hall said.  

But the survival rates Hall cited come from a significant sample size of the herd acquired via Wyoming’s Mule Deer Monitoring Project. That multimillion-dollar surveillance effort, launched in 2022, is generating data about the state’s 37 mule deer herds, which have a combined population of roughly 300,000 animals. 

The project affixed 330 GPS collars onto 200 does, 100 fawns and 30 bucks from five focal mule deer herds: the Wyoming Range, North Bighorn, Upper Shoshone, Sweetwater and Laramie Mountains herds. More focal herds will be identified in future years. 

Based on this dataset, winter mule deer mortality rates are much less dire statewide. 

“Winter doesn’t affect mule deer the same across the state,” Hall said. “We have pretty concerning survival numbers from the western part of the state — particularly the Wyoming Range — but we see notably different trends in areas that have experienced a different version of the winter.”

Pockets of death

Combining numbers from the five focal herds, statewide survival rates on April 13 registered at 75% for does, 78% among bucks and 61% for fawns. 

Northern Wyoming herds — North Bighorn and Upper Shoshone mule deer — have fared the best, with more than 90% survival of does, the reproductive engine of herds that are most important to populations. In the Sweetwater Herd, which dwells in central Wyoming’s Granite and Green mountains, doe survival was 86%. In the Laramie Mountains, some 81% of marked does remained alive. 

“I feel really grateful that we have these kinds of data to lean on,” Hall said, “because we can see the landscape through the deer’s experience and begin to understand winter isn’t created equal for everyone.” 

The winter of 2022-’23 has already claimed more than half of 200 GPS-collared Wyoming Range mule deer does that were alive going into winter. Between March 30 and April 13, 20% of all marked does — represented in red in this graph — died. (University of Wyoming graph modified by WyoFile)

Where it’s at its worst in the Wyoming Range, 2023-’23 will go down as easily the deadliest winter in the modern era for a mule deer herd that’s been closely studied for more than a dozen years. The two most recent severe winters for the herd, in 2016-’17 and 2018-’19, killed only 30% of does, whereas winter 2022-’23 already exceeds 50% mortality. 

Once 50,000-plus-deer strong, the Wyoming Range Mule Deer Herd is among the largest mule deer herds in the United States. It’s renowned for producing big-antlered bucks that attract trophy deer hunters from around the state and country. 

The Wyoming Game and Fish Department updated its fall 2023 hunting season proposals for Wyoming Range deer in winter’s wake. In the Wyoming and Salt River ranges and beyond in western Wyoming, mule deer rifle hunters will have a one-week shorter season. State officials are also planning to implement a new antler point restriction, requiring that any mule deer harvested have three points or more on either antler. Last, youth hunts have been altered to exclude does and fawns.

Biologist Gary Fralick covers a deer’s eyes to keep it calm while large carnivore biologist Ken Mills removes the hobbles prior to release near Big Piney in March 2017. (Mark Gocke/Wyoming Game and Fish Department)

Game and Fish biologist Gary Fralick, who’s in his third decade of working with Wyoming Range mule deer, described these adjustments as “substantial changes.” 

But some hunters and outfitters want to see the state go even farther to protect the health of the herd. 

“What’s it going to hurt, if you shut some areas down for a year or two?” said Rock Springs resident Joey Flaigl, a co-founder of the Muley Fanatic Foundation whose deer hunting grounds are in the eastern Green River basin. “That way you’re totally avoiding someone harvesting any deer whatsoever. Give it a try.” 

Suspend the hunt?

Faigl recalled totally suspended hunting seasons in the 1980s in response to severe winters. The tactic worked, he said, and populations surged as seasons were eased back open. 

Pinedale resident Paul Ulrich, who hunts Wyoming Range deer in the La Barge Creek area, said he and his family would be willing to give up hunting the area while the herd is on the mend. 

“We love to hunt — it’s what we do all fall — and for Wyoming’s wildlife population, if it means us taking a year or two off, it’s the right thing to do,” Ulrich said during the Pinedale town hall meeting

Total suspensions of the hunting seasons were not on the table during Game and Fish’s deliberations this winter, Fralick said. Doing so, he said, wouldn’t have many benefits. 

“Hunting bucks won’t have any negative influence on the population’s ability to increase,” he said. 

Faced with a half-sized herd, other mule deer hunters want to see the state take other steps to reduce hunting pressure in the Wyoming Range. 

A hunter harvested this Wyoming Range mule deer in September 2022. (Mike Koshmrl/WyoFile)

“This year is going to make 2017 look like a cakewalk,” said Freedom outfitter Ted Jenkins, who guides hunters on both sides of the Greys River.

In Jenkins’ view, now is the time to phase out “general” license deer hunting in the region. Those licenses can be bought over the counter by Wyoming residents, the effect being that there’s no real cap on hunter numbers. 

“I’ve guided up there since 1995, and I’ve increasingly seen — year after year — the hunting pressure get worse and worse and worse,” Jenkins said. “Where’s our line in the sand? When do [numbers] get low enough, to the point where they agree that it’s time to make the change?”

Jenkins did not favor suspending the hunting season. He’s aiming to take out two to four guided mule deer hunters this fall, down from the six to 10 he guides in a typical season. 

“I think I’m going to be pushing it to do that,” Jenkins said. “I think all of us have lost prospective clients for this year and in the next few years, obviously. And I don’t anticipate myself hunting for many mule deer or antelope for the next five to seven years.” 

The Wyoming Game and Fish Commission is considering the department’s amended hunting season proposals during an all-day meeting on Tuesday. Attendees can tune in via YouTube and give public comments via Zoom.  

A mule deer born in 2017 called MFFO stands in a clearing in the Wyoming Range in 2020. He was born at the end of a severe winter, and his mother had very little body fat remaining. Even at 3 years old, he remained small for his age, leading researchers to use him as an example of how maternal condition at birth can influence the lifelong size of her offspring. (Photo by Kelly Russo)

Because of deep snow on winter ranges and dying deer, the commissioners are also weighing whether to delay the May 1 shed antler hunting season. Chief Game Warden Rick King told commissioners Monday that his recommendation would be to postpone the popular antler gathering season on public land.

“Big game animals are still on their winter ranges — they’re not moving and not showing any indications they’re going to move,” King said. “The conditions on the ground are such that it doesn’t look like things are going to change much in the next week or two.” 

Commissioners did not vote on the recommendation, however, and will instead consider whether to delay the shed hunting season at a special meeting next week.

This story was updated to include information about the shed antler hunting season. —Ed.

Mike Koshmrl reports on Wyoming's wildlife and natural resources. Prior to joining WyoFile, he spent nearly a decade covering the Greater Yellowstone Ecosystem’s wild places and creatures for the Jackson...

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  1. They need to suspend hunting in all the eastern wyoming counties as well. This year on our hunt we seen 0 deer. We have been noticing a decline over the past 5 years but it’s almost to the point of non existence. The season must be halted for a few years to let the herd rebuild.

  2. Why do we not listen to the professionals or trust the science? This scarcity mindset, irrational thinking will get us the opposite of healthy wildlife and is in direct opposition to the North American Model of Wildlife Conservation.

    When we had far fewer wild others, Teddy Roosevelt era conservationists did NOT ban hunting. The passionate few before us empowered the hunter conservationist to grow the opportunity not divvy up the remnant game populations or remove hunting. They focused on protecting habitat, increasing opportunity for hunting and creating value in wildlife which has had impacts on people and wildlife for generations; all of us included. That abundance thinking is needed now to motivate the hard work of positive action.

  3. Quoted in the article, Mr Jenkins would like to see Wyoming residents lose their hunting rights. Of course he will happily accept less competition for his out of state wealthy clients. How many Wyoming residents travel across the state to hunt in the Wyoming Range? A proposal such as eliminating general licenses is blatant self serving concept. The proper way to manage this is to limit hunting in hard hit areas, not reduce Wyoming residents hunting rights. Mr Jenkins, Take your clients to less hard hit areas.

  4. Procure a pellet suitable for these critters to consume from a supplier when the need arises and feed them. Set up an account for such a need and keep the legislator’s hands out of it!

  5. I want to know why the WGFD didn’t implement a feeding program for the mule deer? They committed to never allow the mule deer to starve through another winter similar to the one experienced in 1991-1992.
    A supplemental deer feeding program would have reduced mortality rates. Why wasn’t their emergency deer feeding program implemented?

  6. I think that the Game and Fish close deer hunting down for a few years to rebuild the herds back up.

    1. I can’t even picture our G&F not feeding the premier deer herd in our state. The idea that it hurts rather than helps is an absurd theory. Don’t they see deer feeding on hay stacks or alfalfa fields in the winter, or is it they don’t want to spend the money. I’m sure they lose some of those deer, but not lose the majority of the herd.

  7. Wyoming is Wildlife. If the numbers I am hearing of winter kill deer and Pronghorn are ever close to being accurate, hunting in critical areas need to be closed for one or two years. Let us hope we don’t have back to back critical winters in 2024 or 2025.

    1. CWD never goes away even these winter killed animals remains who are CWD positive will pass this on to the environment which they probably acquired it from. No know eradication of CWD last I read. Wyoming raised nonresident licenses 30% on some Game so it’s interesting on an income revenue for the state when it’s an obviously needed pause this year on all big game animal harvests.

    2. The deformed protein – called a prion – that causes CWD can remain viable in the environment for over a century in the right conditions. Example: soils containing a fair amount of clay . A prion is neither virus nor bacteria , it isn’t even an organism but it sure does affect them. Millions of different proteins in the biologic universe and this one keys in on the spinal cords, lymph systems , and eventually the brains of ungulates. I would say it is nigh impossible to eradicate.