Phantoms

It had been 10 years since district wildlife managers across the Southwest Region of Colorado Parks and Wildlife (CPW) were first tasked with trekking into the dark timber in some of the state’s most remote places to deploy trail cameras. The goal was to capture images to monitor one of Colorado’s most mysterious wildlife species.

In meeting rooms across the region, CPW Wildlife Research Scientist Jake Ivan posed a big question.

“What do we think? Is this something we want to keep doing?”

Colorado’s phantom felids

Given the arduous work required to monitor Canada lynx, Ivan wouldn’t have been surprised if field staff had a desire to scale back. Instead, the response was a resounding commitment to push beyond the original 10-year study commitment.

“The physical effort required is daunting, but it’s always rewarding,” said District Wildlife Manager (DWM) Nate Martinez of Pagosa Springs.

“In nearly every trip to the high country in the spring when retrieving these cameras, I find that I’m certainly the first human to access any of the trails that year. Long, steep hiking trips — one of mine is an 18-mile up-and-back hike — send your demeanor on a rollercoaster ride; moments of appreciation for the awe-inspiring beauty and solitude, moments of vulnerability realizing if you get into a bind that there’s no one else around, moments of exhaustion and frustration. I often find myself struggling to motivate myself for the longest trips, but once they’re done, I feel so accomplished and empowered.”

Each year, CPW combs through as many as 500,000 images from trail cameras placed across 35 survey units across southwest Colorado, primarily in the southern San Juan Mountains. The goal is to monitor the proportion of habitat in the San Juans that is being used or “occupied” by lynx each year and to track that metric over time.

Images are paired with data gathered from track surveys and eDNA collection, DNA extracted from skin cells left by footprints in the snow. All together, the information has illuminated the lives of a species that spends its existence in the shadows.

“It’s so hard to count these things and actually estimate abundance,” Ivan said. “But tracking this year over year, we can estimate occupancy relatively easily, and we assume that occupancy is an adequate surrogate for abundance at some level.” 

Ivan started with CPW in 2010, and his first project was to develop a lynx monitoring program. By 2014, it was fully implemented.

The results have guided the state wildlife agency in its management of the federally threatened species. It has also set an example for how species such as Canada lynx are monitored by the forest carnivore subcommittee within the Western Association of Fish and Wildlife Agencies. That group monitors not only lynx but also fishers, martens, montane foxes and wolverines across the western U.S.

“I don’t want to say it’s perfect, but we’ve gotten decent at this and made something that works,” he said. “Colorado was sort of the first state to have a large-scale, camera-based occupancy monitoring program for any of those species. That idea has become the standard approach for most of those other species. It’s pretty cool to see something you developed get picked up by others and to see it be useful in other places.”

The data collected has led to the publication of research papers documenting breakthroughs in our understanding of the lynx population. Each DWM involved in the project has come away with valuable lessons of their own, whether it’s about lynx, any of the other 960 wildlife species managed by CPW or even about themselves.

For Lake City’s Lucas Martin, the project gets to the core of what being a wildlife manager is all about.

“I feel really fortunate to have started my career working a lot with the lynx reintroduction,” he said. “They are one of the most unique animals, and it’s a lot of fun to learn about them, to see them up close and track them. They epitomize our vision of wild and reclusive wilderness.”

“Pie-in-the-sky” idea

Lynx are native to Colorado and could be found until the 1900s. Most high-elevation forested areas still had lynx populations in the 1800s. But by 1930, the species had become rare. By 1970, the population had been extirpated as the lasting effects of unregulated trapping, poisoning and local habitat loss contributed to the species’ decline and eventual disappearance.

It didn’t take long for leaders at Colorado Division of Wildlife (now CPW) to devise a plan to bring the species back.

“There are lots of great stories on the whole origin, but as the story goes, there is a famous rafting trip that happened down some unnamed river in Colorado between a bunch of biologists and folks higher up in the agency,” Ivan said. “And as the days went on and they spent nights around the campfire trading stories and talking about life, they decided, man, wouldn’t it be great to do something big and bold and consequential, not only for wildlife conservation in the state but for this forest carnivore species that is iconic, that was native to the state, that always used to be here but was extirpated because of, as far as we could tell, human-related activities.

“It went from a pie-in-the-sky idea to something that’s like, ‘Hey, we can do this. Or, we can at least try to do this.’”

By the 1990s, CPW was ready to embark on an effort to contract trappers in Alaska and Canada to bring lynx back to Colorado.

The first 96 were reintroduced between 1999 and 2000. These initial translocations were “hard” releases and weren’t as successful as CPW would have liked. Beginning in 2003, CPW switched to a soft release strategy, where translocated individuals were first held for monitoring at CPW’s Frisco Creek Wildlife Rehabilitation Center outside Del Norte before they were released near Creede in the southern San Juans.

In total, CPW released more than 200 lynx in the San Juans during the seven-year reintroduction phase.

“Scaled-up house cat”

With the newly reintroduced lynx fitted with radio collars, CPW staff conducted initial monitoring efforts from airplanes and on foot. Biologists and wildlife managers searched the snow for tracks and scat, and traplines were set to capture animals with aging or malfunctioning collars.

“Those first few years when they had us collecting scat, those lynx would take us into the gnarliest, most horrible places in the dark timber,” Martin said. “It was so arduous, and a lot of times they’d take ya into super-dangerous avalanche country. Places you just couldn’t go or get into because of snow conditions, but they are custom built for deep snow with their giant feet. That deep snow is a sanctuary exclusive for the lynx to hunt.”

As kittens were born and fewer lynx could be tracked through collar data, a new method was needed to keep tabs on the small population.

“We knew most of the lynx still lived in the southern San Juans, and that was the logical subpopulation to monitor,” Ivan said. “We decided to divide that world up into survey cells the size of a lynx’s home range and do it every year for 10 years.”

Each of the survey cells are 75 square kilometers (46 miles). DWMs, biologists and U.S. Forest Service partners survey a sample of 50 of these cells each winter, either via snow tracking or setting multiple cameras in each, while also setting visual lures that would draw a lynx within sight of the cameras.

Visual lures included items that would typically attract even a house cat. Visual lures draw in a lynx closer to a tree where a scent lure was placed. Scent lures consisted of beaver castor and, of course, catnip oil.

“It’s just a house cat scaled up a few hundred times. That’s all it is,” joked Ivan. “You place a scent lure in a tree, and you have a camera on another tree focused right at that. Just out of sight of the camera on the other side, you have feathers hanging on fishing swivels so they spin real nice and easily in the wind. Farther beyond that, you’ve got CDs on swivels. When the CD spins out in the open and flashes, you can draw cats in from a distance across the valley.”

To set lures and cameras, CPW staff trek into areas far off the beaten path where there is seldom human presence. The terrain can be grueling for even the most fit.

Recently retired Assistant Area Wildlife Manager Steve McClung of Durango never shied away from some of the tougher camera sets. Not only did it teach him about the land in his district, it kept him fit for running ultra-marathons in the mountains.

“This project puts your boots on the ground in places you would normally never go,” he said. “You’re out exploring and finding wallows and benches and areas where these animals are going to be. You never knew what you were going to see out there.

“Sometimes when you’re forced to get out and get on foot for the job, it opens your eyes a bit. That’s what I love about it. It’s fun to look at those empty spaces on the map and know that lynx are living there unencumbered by roads or trails. These are places where wildlife have the opportunity to just be wildlife and not constantly have to worry about people bumping them, interrupting and disturbing them and diminishing the effectiveness of their habitat.”

Some wildlife managers have set cameras all 10 years of the project but never had a lynx appear on camera. One of those is Martinez, who logs roughly 80 miles a year hiking for the project. He said he has lost 40 pounds since moving to his Pagosa Springs district hiking in the San Juans.

Still, Martinez has found value in every outing.

“Those earliest and latest trips, linked with reviewing the camera photos annually, are helpful in gauging annual migration times, mating seasons and birthing seasons,” he said. “I’ve certainly noted an exciting increase in moose numbers over the course of the project. Unfortunately, maybe I’ve captured every other critter you could think of, but never a lynx. But I’ve had unbelievable wildlife encounters and have built character all along the way.”

The lessons learned

Aside from combing through a half million photos a year and snowmobiling nearly 500 miles each winter looking for tracks and scat, Ivan recently paired with the U.S. Forest Service and University of Wyoming to publish new research findings.

Highlighted was a refined understanding of how much good lynx habitat exists in the state, which is substantially less than had been mapped in previous efforts. Also, protected lands are important, as 62% of likely lynx habitat overlaps with areas such as wilderness zones and national parks. It also identified wildfire as the greatest threat to lynx habitat, as fire would destroy the forest understory that lynx rely on for shelter and hunting snowshoe hares, which make up 70% of their diet (with another 28% consists of red squirrels).

Conversely, research showed that beetle kill’s impact on forest health has not had a negative impact on lynx. That revelation was not a surprise to many of the wildlife managers who have been involved in monitoring lynx while simultaneously watching beetle kill spread in southwest Colorado.

“When the beetle kill occurred here, the hare populations went through the roof,” Martin said of Lake City. “It got difficult to trap lynx when we needed to because there was so much food out there the trap was no longer attractive. When we’d have beaver or deer in a live trap, for years the lynx would hit it within a day or two. After the beetle kill, there was such a plethora of food out there, lynx had lost the attractant to bait. Lynx are just so impressive out there where you never see them, living in this beetle kill eating hares and squirrels.”

“Interference competition?”

While the camera sets are intended to detect the presence of lynx, they have also revealed how their population correlates with the presence of other species. 

For example, when an abundance of bobcats appear on a camera, that generally correlates with fewer photos of lynx, Ivan said. The same relationship has been true with foxes.

“Bobcats and lynx, they’re very similar species,” Ivan said. “They’re in the same genus, they’re very similar in size, they eat kind of broadly similar things — although bobcats have a much broader diet ­— but I think the concern there is what we term ‘interference competition.’ The personality of a bobcat is just totally different from a lynx. They’re much more aggressive. And so what we tend to see is when bobcats move up into an area and establish a territory, it isn’t very long before whatever lynx were there just sort of move off, then disappear. It’s sort of a direct-displacement thing with bobcats.

“We noticed a similar pattern with montane foxes up high. And that may be more of a food competition thing because we get lots of photos, a surprising number of photos, of red foxes running by the camera with a snowshoe hare in their mouth. For us to get several photos like that every winter indicates to me that they’re taking a fair number of hares. And maybe that’s the mechanism there for why lynx occupancy tends to decline when that species tends to increase its use.”

Ivan explained there have also been a few positive associations for lynx with other species. One includes coyotes.

“That could be because coyotes are suppressing these other species,” he said. “You have more coyotes, you have less foxes.” 

A deeper dive into the co-occurrence of these species with lynx, based on the camera data collected over the 10-years of monitoring, is currently underway with a Ph.D. student at CSU.

A new way

The last decade has revealed much to wildlife researchers, but CPW continues to adapt when new techniques are presented.

During the 2025-26 winter, a new camera-trapping method was deployed. Ivan has followed the work of Dr. Daniel Thornton, a Professor at Washington State University Pullman, and his graduate students, who have independently monitored lynx in Washington and northern Montana. 

Thornton has had success capturing more lynx photos using “passive” sets that do not rely on visual and scent lures. Instead, the protocol calls for doubling the number of cameras deployed in each unit, but focus is given to common paths such as old trails and logging roads. While there are more cameras to set, it’s less back-breaking days for field staff.

“We always want to improve and make sure we continue to collect the best data that we can,” Ivan said. “Cats are finicky and are particular about certain things. Eventually, their curiosity wears off and they know that tree in that part of their home range, ‘Yes, it smells like catnip, but there’s nothing for me there. I have better things in life to do than check out that tree.’ You got to stay ahead of them and do novel things, and we’re excited about this new protocol.

“Lynx, like us, will take the path of least resistance and often walk those roads. Getting away from baits and lures, you can actually get lots of photos of lynx, and detection probability might even be better. We’re hopeful that works out.”

The same survey units that were surveyed with the “lured” sets will continue to be surveyed with the “passive” sets, to maintain continuity of the data stream and because the majority of lynx in the state remain in southwest Colorado.

Colorado’s population of lynx remains at an estimated 75-100 adults. Ivan said the population has remained stable to the best of CPW’s ability to know and understand. Their population doesn’t grow as quickly as other cat species such as bobcats and mountain lions, which are generalists in terms of habitat preferences and diet. The lynx remains a specialist in its habitat and narrow focus on snowshoe hares and squirrels.

“They really need everything lined up to make a go of it,” Ivan said. “By our standards, we do have fairly high densities of hares in places around the state, but it pales in comparison to the magnitude in Canada and Alaska, the honey hole of lynx range in North America. Those factors prevent the lynx population from exploding and us being able to have hundreds of lynx everywhere in the state. They are where they are.”

For a DWM such as Martin, that just happens to be in his Lake City district, not far from where the first lynx were released and the first kittens were born from the reintroduced population. And he’s not surprised they haven’t moved out to establish more areas of the state.

“Our lynx continue to have good success finding food,” Martin said. “When they have a real abundance of food, there’s no reason to go real far. They’ve got their piece of the forest, and as long as people leave them alone, they’re good to go.

“Powderhorn, Uncompahgre, the Weminuche, the La Garitas, it’s kind of like the last best chunk of Colorado.”

John Livingston is a Public Information Officer for Colorado Parks and Wildlife’s southwest region and is based in Durango.