Colorado Parks and Wildlife is on track to begin releasing gray wolves in Colorado by Dec. 31, according to agency spokesperson Travis Duncan.

The timeline makes good on a mandate approved by Colorado voters in a 2021 ballot question, Proposition 114, and comes after the state’s wildlife agency entered into an agreement with Oregon’s Department of Fish and Wildlife in October to translocate 10 wolves from that state to two areas on the Western Slope, including the Roaring Fork Valley, by year-end.

The update also comes after Colorado Parks and Wildlife confirmed wolves were responsible for a trio of female sheep found dead on a ranch near Walden last Friday, and nearly two years after three similar incidents were reported in Jackson County in a two-month span.

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But the spate of wolf attacks, and the handful of confirmed wolf sightings reported by CPW in recent years, are not an indication that the species population is growing in Colorado — nor are they a reason to doubt the importance of the state’s gray wolf reintroduction effort.

Laptop open and sitting inside of her research cabin on the border of Yellowstone National Park, Joanna Lambert — a professor of animal ecology and conservation biology at the University of Colorado in Boulder — explained why that is the case.

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“The really important first place to begin when thinking about what happens when you put a species back into a system is to think about that system in deeper evolutionary time in the first place,” Lambert said.

Pointing to the classic food web system where apex predators are at the top, prey exist in the middle and vegetation is at the bottom, Lambert noted the hierarchy taught to nearly every student in the country has been in place on earth for millions of years.

For the last million years, gray wolves have been on the North American continent, but only recently — over the last 80 to 100 years depending on where you are in the American West — those wolves have no longer been involved in food webs, the conservation biologist explained.

“Essentially what is going to happen, and we know this from the superb science at Yellowstone National Park where this has already been done, is the food web will be restored to its previous state,” Lambert said.

While gray wolves were present in Yellowstone National Park when it was established in 1872, attacks on livestock in the area of the park and across the nation led to the near elimination of the species in the U.S. by the mid 1900s, according to a history of their populations compiled by the U.S. National Park Service.

By 1978, the gray wolf and all subspecies of the animal had been added to the list of the nation’s endangered species for all lower-48 states except for Minnesota. Then, in 1991, the U.S. Secretary of Interior signed a rule allowing for the reintroduction of gray wolves to Yellowstone before wildlife officials began to relocate dozens of wolves to the park from Canada in 1995 and 1996.

Since 2009, wolf populations at Yellowstone have fluctuated between 83 and 123, with 108 reported in the park as of January, according to federal data.

Lambert cited the wolf reintroduction effort at Yellowstone and its tangible changes in the area’s ecosystem to explain the types of outcomes one might expect in Colorado should the state’s reintroduction effort be successful.

In Colorado, Lambert said the initial impact of the wolves’ reintroduction will be diluted overall. She cautioned that growth of the population depends on variables including disease transmission dynamics, mate availability, drought climate and habitat availability, along with any number of social dynamics between the wolves themselves, and between wolves and people.

If the population reaches between 30 and 50 wolves in Colorado, Yellowstone’s wolf population suggests the impact will come mainly through a change in behavior among prey species such as elk and deer.

“Areas where there has been massive over-grazing and over-browsing by prey species like cervids, or elk and deer, if populations of those prey species are moving differently and therefore consuming food differently, then we might see some regrowth of vegetation just as we have seen at some areas of Yellowstone National Park,” Lambert said.

The Yellowstone wolf reintroduction effort is also key to explaining why wolves are occasionally spotted, or are reported to attack livestock in parts of Colorado without establishing population growth locally.

After being reintroduced to Yellowstone in the mid 1990s, wolves gradually began to connect with other populations roaming places like central Idaho and northern Montana.

“It took a while for that northern Rockies population to get to achieve a certain distribution and density in the first place,” Lambert said. “After that did occur, certainly wolves did start dispersing their way out of what we call the greater Yellowstone ecosystem.”

But for wolves to make their way south to Colorado, they need to cross Wyoming, where they are not included on the state’s endangered species list and where roughly 85% of state land falls under Wyoming Game and Fish Department predator control area rules, which allow for a wolf to be killed at any time without a license.

“It’s kind of running the gauntlet for wolves as they make their way through that predator control area,” Lambert said. “They are very often shot and there are a lot of major highways to get over and wolves do get killed on highways, even in the greater Yellowstone ecosystem.”

While a wolf population does not exist in Colorado today, there are an estimated 4,500 wolves in areas of the upper Midwest, along with roughly 2,500 in the northern Rockies.

As a result of that population growth, lawmakers in recent years have pushed to remove their endangered species list designation at the national level.

Sponsored by U.S. Rep. Lauren Boebert and passed in the U.S. House of Representatives as part of the 2024 Interior, Environment and Related Agencies Appropriates Bill earlier this month, the “Trust the Science Act” is the latest attempt to require the U.S. Department of the Interior to delist gray wolves as endangered species across the continental U.S.

She knows of the bill, but Lambert said she was not familiar with the exact language of the proposed legislation, and its name seemed perplexing, especially when comparing today’s U.S. wolf population to the estimated two million wolves that once populated North America.

Additionally, Lambert noted that the distribution of wolf populations across the lower-48 states in the U.S. has only reached 9% or 10% of what it once was.

“That is indeed how the U.S. Fish and Wildlife Service ultimately removes animals or plants or endangered species from the list,” Lambert said. “It is to evaluate in detail whether the species or population of concern has met the recovery requirements. I don’t know how those numbers, in light of the former population abundance and distribution of gray wolves, it doesn’t really compute in terms of recovery. From many biologists’ perspective, those numbers and that distribution don’t meet the biological definition for recovery of these species.”

According to Colorado Parks and Wildlife, the removal of gray wolves from the nation’s endangered species list could compromise a recent rule enacted by U.S. Fish and Wildlife that designates Colorado’s future population as experimental and would return their management to the state.

The federal population designation will provide for allowable, legal, purposeful and incidental taking of a gray wolf threatening livestock or working dogs, while also providing for the conservation of the species, and carving out special rules for tribal lands.

According to Duncan, CPW wildlife officials worked closely with U.S. Fish and Wildlife to craft their own rules in a way designed to ensure that if the delisting scenario does play out, and the state wildlife agency takes over management of the population, “the tools available really would not change.”

With more than 35 years of conservation biology and experience across multiple continents, Lambert said she supports the experimental population rule approved by the federal government and sees it as an important compromise among stakeholders.

In addition to her teaching and research positions, Lambert sits on the board of the Rocky Mountain Wolf Project, an organization that pushed for Proposition 114 ahead of its 2021 approval and is now focused on providing education and working with ranchers, farmers and other groups on how to legally deal with wolves that may encroach on their livestock.

“One thing that I have learned over and over and over again is that extreme views on any kind of a recovery on an endangered species don’t work and that everybody has to come to the table and have difficult conversations about what compromises are going to be made,” Lambert said.

Aside from a positive impact on the state’s ecosystem, Lambert said another key indicator of successful reintroduction primarily involves humans and their ability to coexist with wolves.

“I think it is important always to pull the lens out and to remind the audience of where we are right now on earth,” Lambert said. “Animal species, plant species are blinking out without us even knowing it. I feel like the burden of that, the emotional burden, no matter who you are, from whatever walk of life, we are all aware of this at some level.”