As wildlife advocates push forward a ballot measure this November to ban the public hunting of mountain lions, lynx and bobcats in the state, Colorado Parks and Wildlife is working on a management plan for the lions that reside in the eastern half of the state.

The plan largely mirrors the West Slope Mountain Lion Management Plan, enacted in 2021, with both seeking to maintain stable populations of mountain lions across the state by outlining the agency’s approach to annual mountain lion harvests.   

The proposed plan, known as the East Slope Mountain Lion Management Plan, was presented to the Parks and Wildlife Commission on Friday, Aug. 23, and will be before the commission for approval in November. Any new regulations required by the plan would be voted on by the commission in January 2025.

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Dallas May, chairman of the commission, made clear at the Aug. 23 meeting that the ballot initiative and the proposed management plan are separate issues and will “proceed at this time on separate paths.” 

As an agency, Parks and Wildlife has said it will not publicly support or denounce the ballot measure, leaving it to the will of the voters.

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“CPW will continue its work on the east slope lion plan and will respect the will of the voters on Initiative (127) once that is determined,” May said.

A shifting management approach

Colorado Parks and Wildlife estimates that there are between 3,800 and 4,400 mountain lions in the state. Mark Vieira, the agency’s carnivore and furbearer program manager, told the commissioners that more of the lion population lives to the west.

“These animals aren’t endangered or threatened in any way,” Vieira said. “In fact, recent data collected in Colorado shows they are present at relatively high densities on both the west and east slopes.”

The east and west mountain lion plans represent a different regional approach to management than what was historically done.  

The plans consolidate 19 previous management plans — most of which were from 2004 — that covered smaller geographic regions to better manage the “solitary, low-density and wide-ranging” nature of the carnivores. The two regional plans split the state into three main management areas for mountain lions, representing the northwest, southwest and north-central Front Range. The southeast plains are not included in either plan because the region does not contain lion habitat.

Both regional plans create guidelines for management over the next 10 years.

Vieira said that the eastern plan borrows significantly from the Western Slope plan, which he said “has shown itself over the last three lion seasons to be a successful and conservative model of lion management.”

The primary difference between the regions is that lions in the eastern part of the state are living in closer proximity with more humans, Vieira said.  

“We’ve got these high densities of lions with high densities of people recreating and participating in the outdoors,” Vieira said of the eastern region.

As a result, the eastern side of the state sees more human-caused mortality of lions not related to hunting —  including lions that are hit by vehicles — which can impact management slightly, he added. On average over the past three years, such incidents were responsible for 27.7% of deaths in the eastern region, according to the report. In 2018, they were responsible for around 9% of lion deaths in the western region. 

The overall objective of the plans is to maintain the state’s current number of mountain lions to ensure they continue contributing to the state’s biodiversity. According to the plan, lions add to the ecosystem in various ways, including removing diseased and injured prey, guiding landscape conservation by spreading nutrients and more. 

What the plan tells us about the harvest of lions in Colorado

To make sure populations don’t decline, the plan proposes two thresholds, which when triggered would independently impact the number of hunting tags issued. These proposed thresholds are the same as in the Western Slope plan.

The first threshold places a cap on the number of human-caused deaths to mountain lions. This cap would exclude mountain lions killed by the wildlife agency due to dangerous behavior or their presence in a dangerous location, which Vieira said is historically one animal per year on the east slope.

“We believe it is important to consider all human-caused mortality when we develop this threshold,” Vieira said. “The biological impact to a lion population is the same whether the animal is taken by harvest, roadkill or on a sheep depredation.”

It is proposed that the three-year average of human-caused mountain lion deaths cannot exceed 17% of the total population of lions.

Within this, Vieira said the annual harvest rate is expected to be around 12% of the population. This percentage allows “a level that is both sustainable and not likely to cause social disruption in a population,” he added.

For the past three years, an average of 505 lions have been killed via hunting in Colorado.

The second threshold places a cap on the number of adult female lions — those that are older than 3 or that show evidence of nursing — that can be hunted each year. Under this, adult females cannot make up more than 22% of the annual harvest. This will help prevent a decline in lion populations as females “represent the biological engines” of the carnivores, Vieira said.

In an April 2024 document on lion management, Colorado Parks and Wildlife stated that females generally account for 40% or fewer of hunted lions.

The method of hunting is important in maintaining this, according to Parks and Wildlife. Over 90% of Colorado’s lion hunting is done using hounds, which “allows hunters to be selective of gender based on the track size and the snow and being able to sex an animal while it’s treed,” Vieira said.

“In states that don’t have the use of hound hunting, like Oregon and Washington, the proportion of their harvest that’s female is much, much higher,” he added.

If triggered, the plan proposes that each threshold would independently reduce harvest allocations by 5% for three years.

These thresholds in the proposed eastern plan would result in a “reduction of 53 lions from our current east slope harvest limits,” Vieira said, reducing it from 208 lions to 260 in 2025 and 155 in 2026.

In addition to these thresholds, the east and west slopes have significant portions of “high-quality lion habitat” where there is “virtually no lion harvest,” Vieira said. In the west, 49% of the landscape falls under this category. In the east, it accounts for 47%. The existence of these areas is “an additional safeguard in (Colorado Park and Wildlife’s) lion management strategy,” he added.

There are two mountain lion hunting seasons in Colorado. The regular lion hunting season begins the day after the fourth deer and elk rifle season ends — Nov. 24 this year — and runs through March 31. A second season from April 1-30 can be held depending on the number of lions killed in the primary season. The April season was canceled this year.   

These April seasons would “be closed for the first three years under this plan to allow hunter behavior and harvest patterns to stabilize,” Vieira said.

The agency can also annually regulate hunting season dates, open game management units or harvest limit groups, methods of take, harvest reporting requirements and harvest limits. As with all big game in Colorado, electronic calling is an illegal method of hunting for lions.

Broadly speaking, “hunting is an important tool that we have in our toolbox” used to change the distribution of the animals, take care of conflict animals and more, Vieira said. 

“Lion management can at times be portrayed as a question of one value versus another,” Vieira said. “However, (Colorado Parks and Wildlife) must balance that full spectrum of values to benefit Colorado citizens and visitors.”