The Return of Wolves to Colorado Will Change Elk Looking There. Here is How

This year’s elk season is a historic one in Colorado. It’s the first time in more than 80 years that big-game hunters have shared the landscape with an established population of gray wolves. This is thanks to an ongoing wolf reintroduction plan that was voted in by a slim majority of Coloradans in 2020 and has rankled hunters and outfitters, who are now worried about the impacts those wolves will have on the state’s world-famous elk herds.

Their concerns are warranted. Colorado is home to more elk than any other U.S. state, and it’s far-and-away the most popular elk-hunting destination for nonresidents. A staggering 186,028 people hunted elk in Colorado in 2023 compared to 52,951 in Wyoming and 87,864 in Idaho. But all this hunting pressure (from both residents and non-residents) is mounting, and as hunters complain about overcrowded public-land units, the state is cutting back on out-of-state elk tags. Continued development and land-use changes, along with the spread of chronic wasting disease, are impacting Colorado’s elk herds as well.

Wolves not only compound these concerns. They embody them. And as hunters in other Western states share stories about wolves taking a bite out of their big-game herds, some of them are starting to view wolf reintroduction campaigns as a way to eliminate or restrict hunting altogether.

Like it or not, though, gray wolves are here to stay in the Centennial State. Colorado Parks and Wildlife has no choice but to follow its mandate to restore a sustainable population of wolves to Western Colorado — a process that began in December when CPW officials released the first of 10 Oregon-born wolves into Grand and Summit counties. CPW is now planning its next release for this coming winter, using wolves sourced from Canada. There is also evidence that wolves have been returning to Colorado on their own since 2004.

Read Next: Coloradans Vote Down a Big Cat Hunting Ban in a Massive Win for Hunters and Conservationists  

As of Nov. 5, CPW is monitoring nine wolves in the wild. And although this isn’t enough to noticeably impact big-game species like elk, it’s only a matter of time. Experts know that wolves will reestablish a viable population in Colorado because we’ve seen them do just that in other Western states like Wyoming, Idaho, and Montana, where they were either reintroduced or recovered on their own. (Wolf biologists in Idaho and Montana say it only took about 10 years for gray wolves to reestablish themselves there.) So, by looking closely at how wolf recovery has played out in those Northern Rockies states — and how elk herds have fared — a rough idea of what to expect in Colorado emerges. 

Wolves, of course, are unpredictable, and Colorado is different in many ways from other Western states. It can also be hard to get straight answers about gray wolves because they belong to such a controversial species that generates strong emotions. As with other wildlife management controversies, the best way to cut through this noise is to follow the science. So, drawing on decades of trends and research around wolves and elk in the West, here are five conclusions hunters can reasonably draw about what wolves will do to Colorado’s elk.

Wolves Will Change Elk Behavior

Wyoming outfitter Bill Perry has been guiding elk hunters on the outer fringes of Yellowstone National Park since the 1980s. And he’ll tell you that the hunting opportunities there have changed since wolves returned to the landscape.

“Before [the Wyoming wolf reintroduction] the hunting was really good, and it still is. The elk have learned to live with them, and according to Game and Fish, our elk numbers are above objective,” says Perry, who primarily hunts Unit 60 on the southeast corner of Yellowstone National Park. “But now, hunting them it’s a whole different thing. The bulls used to be more vocal, and they would be down in the creek bottoms where you could bugle and get to them. Now they’re just as high as they can go, and the wolves have pushed some of them out of the mountains entirely. We have elk now in the plains south of Cody, an area that never used to have any elk on it.”

Perry says this change has led to a loss of hunting opportunities for some hunters who can’t access those areas. He adds that the trend has been even more evident in Montana and Idaho, both of which have significantly more wolves than Wyoming. (The latest estimates show that Wyoming is home to around 350 wolves, while Idaho and Montana have more than 1,000.)

“The guys I know, especially in Montana,” Perry adds, “they’re gonna tell you that the numbers of elk they’re seeing are down.”

Wolves Won’t Eat All of Colorado’s Elk

Biologists with the Wyoming Game and Fish Department caution against automatically linking wolves and declining elk numbers in any one location, however. Wolf predation can certainly play a role in reducing elk numbers, they say. But so do other things like hunter harvest, habitat loss, winter kill, disease, and in some places, other predators like bears and mountain lions.

“I always use the word ‘potential’ because it’s not a given,” WGFD wolf biologist Ken Mills explains. “It’s not A plus B equals C where you have wolves and you have elk, and therefore wolves are going to reduce elk numbers. It’s not that simple.”

Looking north to Wyoming can also be confusing because the state’s overall elk numbers have actually increased since the mid 1990s, when wolves were reintroduced to Yellowstone National Park. The same goes for the annual statewide elk harvest, according to Dr. Kevin Crooks, who runs the Center for Human-Carnivore Coexistence at Colorado State University. He says this is proof that Coloradans can have both wolves and big game on the landscape.

“Colorado has a robust elk herd, more than any other state — the most recent estimates are just over 300,000 [animals]. And it’s unlikely that wolf predation will significantly decrease the total number of elk across the entire state,” says Crooks. But he adds that in some situations, wolves might have local impacts on some elk herds, particularly during harsh winters or times of drought.

“Wolves can also change what elk do and where elk move,” Crooks acknowledges, “which might make hunting more challenging in places.” 

In other words, even if wolves aren’t consuming large numbers of elk, their mere presence can change elk behavior in some instances. It’s only by zooming in on certain areas within a state that these shifts start to emerge. WGFD wildlife biologist Aly Courtemanch monitors some of the elk herds in Northwestern Wyoming, where gray wolves are most abundant, and she says there’s a lot more nuance to the statewide elk population increase.

Read Next: New Utah Study Shows Elk Leave Public Ground During Hunting Season, But Issuing Private-Land Tags Send Them Back

“Wolves are really only found in the northwestern corner of the state,” Courtemanch tells Outdoor Life. “Most of that increase in [our elk numbers] has happened on the eastern side of the state, where we don’t have wolves, and it’s mostly been driven by things like land-use change.

“On the Western side, there are pockets where elk have decreased for various reasons, but overall those herds have been fairly stable in recent decades,” she continues. “Of course, wolves eat elk. And we know they have an impact on elk. But we haven’t seen it to such a large extent that it’s driving population numbers.”

Mills says the best way to understand the real impacts that wolves are having on elk in the West is through extended research. He says there hasn’t been much of this done in Wyoming outside of Yellowstone NP, and he points to several studies that have been conducted in Idaho and Montana.

One such study, conducted in Montana’s Bitterroot Range and published in 2016, found that more aggressive harvest regulations on black bears and wolves did not influence elk calf survival or recruitment there. The study also noted that mountain lions were the predators most responsible for killing elk, as lions killed an average of three times as many elk as wolves.

Another Montana study that looked at mule deer populations across the state drew similar conclusions, according to longtime Montana wolf researcher Diane Boyd, who presented some of this data in a 2021 wolf information session hosted by CPW. (There are also roughly three times as many mountain lions in Montana as there are wolves, Boyd pointed out during her presentation.)

Boyd also said that as a general rule, harsh winters kill significantly more elk than wolves and other predators do. During the brutal winter of 2022-23, for example, wildlife managers in parts of Northwest Colorado saw cow elk populations decline by around 60 percent.

“So, we can add up all this data. We can talk about mountain lions, and we can talk about the impacts of hunting — and I am a hunter. We’ve also got grizzly bears and black bears,” Boyd explained in the webinar. “But winter, far and away, has the biggest significant impact on big-game animal populations.”

Wolves Will Reduce Elk Hunting Opportunities in Certain Public-Land Units

A 12-year elk survival study conducted by the Idaho Department of Fish and Game puts a finer point on the combined toll that harsh winters and wolf packs can have on elk. The study was led by IDFG senior research biologist Dr. Jon Horne, who joined Boyd in presenting some of his findings to Colorado wildlife officials in 2021.

The Idaho study tracked 1,200 collared adult female elk and 800 collared 6-month-old elk calves across all 29 of the state’s elk management zones between 2004 and 2016. Horne and the other researchers concluded that more elk were killed by wolves in areas with marginal winter range. Unsurprisingly, those impacts were more noticeable in areas with larger wolf packs. They also saw variability: Wolf predation of elk increased during high-snow years and decreased during low-snow years. 

All this means that elk living in certain habitats — such as areas with deep snow — are more vulnerable to wolf predation during severe winters. Over time, those elk are either killed or they relocate. Unfortunately for hunters, Courtemanch says this means that some elk herds have shifted their distribution from areas where they were historically found during hunting season.   

To demonstrate these shifts, Horne pointed to two charts that showed elk populations as they related to management objectives in all 29 of Idaho’s elk management zones. These charts showed how over the years, the presence of wolves has led to more units with too many or too few elk.

“This is where a lot of the research and concern about wolf predation on ungulates comes into play,” Horne said. “A lot of these zones that are below management objectives are in the backcountry of Idaho. And that’s what Idaho is famous for, these backcountry elk hunts [for public-land hunters].”

IDFG’s latest elk management plan shows that wolves are a limiting factor in 11 of the state’s 29 elk management zones, and the elk populations in four of those zones are considered “highly limited” by wolf predation. To Horne’s point, these are primarily backcountry areas in the north-central part of the state. This is where gray wolves are most abundant, and where elk declines have been “precipitous,” according to IDFG.

“Over the last 20 years, some backcountry elk populations declined between 34 and 80 percent based on elk survey data,” reads the 2014 to 2024 management plan. “Subsequently, available elk tags have been reduced by as much as 52 percent.”

One of the four zones considered “highly limited” by predation, the Lolo zone is a prime example of a public-land unit where elk hunting opportunities have been reduced since wolves were brought back to the state. The Lolo’s elk population peaked around 16,000 in 1989 and has declined ever since. The most recent estimates by IDFG in 2017 showed around 2,000 elk there.

“Hunting in the [Lolo] zone has been extremely restricted since the late 1990s,’” the agency explained in a 2020 press release. “Rifle hunting for bull elk [has been] reduced by half and all cow hunts have been eliminated.”

These declines in the Lolo have persisted even though IDFG began taking wolf control actions there in 2011, removing an average of 14 wolves annually from the unit. (This is in addition to the average of 21 wolves that are taken each year by licensed hunters and trappers, IDFG says.)

Horne cautions against using the Lolo as the archetypal public-land elk unit. “Elk in Idaho are not created equal,” he told CPW officials, “and different places can have different experiences.” He says the Lolo has a long history of elk populations in flux, and that those populations were already starting to dip by the mid-90s, when wolves were brought back to the area.   

But regardless of whether wolves (or other predators) can be considered the main driver of elk declines in the Lolo, it’s clear that wolves have played a major role in preventing those elk from recovering. That’s according to IDFG biologist Craig White, who was studying elk and wolves in the Lolo during the same time Horne was conducting the 12-year elk survival study.

In a 2010 article, White explained that between 2005 and 2008, IDFG documented wolves removing around 20 percent of cows each year. He said during that time, elk survival rates were down to around 75 percent without any cow harvest by hunters, compared to 89 percent during the pre-wolf days when hunters could still take cows.

Read Next: The Ultimate Guide to Elk Hunting

“Perhaps even more alarming is that winter calf survival is only 30 to 52 percent in areas with relatively high wolf numbers. This compares to calf survival rates of 71 to 89 percent prior to 2004 when wolf densities were lower,” White wrote at the time. “Several factors played a role in this decline [of elk populations in the Lolo], but today, wolves are the primary reason that elk are still trending down in this zone and cannot recover.”

IDFG spokesperson Roger Phillips says these declines, combined with the growth of elk herds in other parts of the state, can lead to the misconception among hunters that all the elk are being driven out of the backcountry and into the front country. That’s not always the case, he explains, even though it might hold true for certain herds in some areas.

“Our radio collar data does not back that up,” Phillips tells Outdoor Life. “What he have is rapid growth of [elk] herds in those front country and ag areas, and a long, steady decline in some of those backcountry areas. It’s not necessarily a migration.” 

Wolves Are Not Ecological Saviors, and They Won’t Solve CWD

One of the most common arguments made by wolf-restoration advocates is that wolves are a keystone species that evolved alongside elk and other ungulates. And that by preying on ungulate populations, which would otherwise eat themselves out of house and home, wolves and other predators help maintain balance in an ecosystem.

At its core, this argument seems to make sense. Look at a city like Montreal or Pittsburgh, where whitetail numbers are so out of control that tax-funded sharpshooters are culling them, and you can see what happens when a deer population exceeds the carrying capacity of a given ecosystem. But this line of thinking overlooks the sweeping habitat changes that have occurred throughout North America over the last century and the fact that a large part of the Lower 48 is now basically uninhabitable for wolves and other apex predators. It also discounts the important role that humans, another predator species, play in managing ungulate populations.

Anti-hunting groups like the Center for Biological Diversity also contend that restoring wolves and other apex predators to an area where they’ve been absent will actually improve the overall health of that ecosystem. As an example, they often point to the idea of trophic cascades in Yellowstone National Park — the theory that bringing back gray wolves has allowed certain woody plants (and favorite elk foods) like aspen trees to recover, thereby improving the overall health of the landscape.

But this theory has been somewhat debunked in recent years. A 2021 study suggested that the reintroduction of gray wolves did not cause as much aspen regrowth as once thought. Another study published in March reached a similar conclusion.

Mills agrees, and he says that some of the “observational science” behind the trophic cascades theory isn’t widely agreed upon. He also casts doubt on another popular idea that’s been promoted by wolf advocates in Colorado recently: That wolves can help solve the CWD problem by having a “cleansing effect” on the state’s infected deer and elk herds.

“There is no science to indicate that CWD is going to be reduced because wolf predation is on the landscape. There will be claims that there’s science, but those are modeling exercises based on estimations of wolf predation,” Mills says. “You’re also dealing with a disease that has a multi-decade persistence in the soil … so I’d say that wolf predation eliminating CWD is unrealistic.”

When pressed by CPW staff during the 2021 webinar, IDFG’s Horne had a blunt response to the question of whether wolves can help eliminate CWD from deer and elk populations: “No.”

Which Is Why Colorado Needs to Manage Its Wolves in the Future

While advising CPW officials about what to expect as wolves reestablish themselves, both Boyd and Horne spoke to how quickly wolves re-colonized the available habitat in Montana and Idaho. Colorado wildlife managers should “expect the unexpected,” Boyd said, and she pointed to a 2017 map that showed the dispersals of 297 radio-collared wolves from Montana over a 15-year period.

“They went to two countries, seven states, and two provinces from our core populations [in Montana]. And that’s what you need to know about wolves,” Boyd said. “They live by their feet, as the old Russian proverb says. You will have wolves going everywhere. And they will show up in places you aren’t expecting them.”

Boyd mentioned this to emphasize that Colorado wildlife managers will have no choice but to manage wolves as they continue to disperse. This includes considerations for lethal management, she said, because there will be more conflicts with ranchers and other landowners — these are already happening —  and wolves will get killed.

Read Next: As Wolf Management Debate Reaches a Fever Pitch, the Interior Department Hires a National Mediator

It’s also important to note that one of the reasons Wyoming, Idaho, and Montana still have robust elk herds is because they’re able to manage their own gray wolf populations. (Gray wolves are not a protected species in those states, but they remain federally protected in Midwestern states, where hunters say wolves are having major impacts on deer populations.) So when state wildlife managers see imbalances in predator-prey dynamics, they can adjust accordingly.

Mills says that over time, continued management by state wildlife agencies can help address some of the uncertainties around wolves. And he says that in his experience, Wyoming’s ability to manage its gray wolf population has helped keep elk populations stable, while at the same time increasing the overall social tolerance of wolves. 

“But if you don’t manage wolves on the local level, and they’re protected under the Endangered Species Act, you don’t get that,” Mills says. “I think it’s a cautionary tale for Colorado, too, because there’s already a strong push there to never hunt wolves. And I think that’s a losing game when it comes to building a tolerance for wolves on the landscape.”