Using data collected through GPS collars and cameras, Colorado Parks and Wildlife has “confirmed a robust mountain lion population” present on the Western Slope including in some areas where the figures “exceeded modeled estimates.”

A CPW news release announced results from the first two areas of the agency’s 10-year Western Slope Mountain Lion Density Study that began in 2020. The first study area focused on Middle Park between Kremmling and Granby. The second study area was located in Gunnison Basin.

CPW Carnivore and Furbearer Program Manager said the agency was “satisfied to see that our measured estimates of lion density from our winter field seasons are equal to, and in some cases higher than, the lion density projections we use when making harvest management decisions.”

To collect the data, wildlife biologists, district wildlife managers and researchers worked to capture, mark, collar and then monitor mountain lions while also deploying cameras to track the animals’ movements.

According to CPW, there are 3,800-4,000 mountain lions in Colorado today.

The agency said 48 lions were collared in the Middle Park area and just over 50 were collared in Gunnison Basin.

After two years of collection in each of the study areas, an analysis of the data was completed by a CPW staff biometrician, a statistician who uses mathematics to analyze biological data.

Results of the camera-based mark-resight estimates in Middle Park averaged 2.5 independent lions per 60 square miles during the winters of 2021-22 and 2022-23.

In the Gunnison Basin, CPW observed an average density of 4.2 independent lions per 60 square miles in the winters of 2022-23 and 2023-24.

The study involved independent lions, including adult age and sub-adult age animals, which typically disperse from their mother at average age of 14-15 months.

The mountain lion density figures were estimated using “camera-based mark-resight estimates.” In the “mark phase” of the study, ear tags and GPS collars were placed on mountain lions who could then be spotted in a “resight phase.”

Mountain lions that were not marked and collared were also spotted by CPW staff using the cameras, allowing researchers to estimate the total population size in the study area using mathematical modeling, according to the state wildlife agency.

“This combination of GPS collars and ear tags on lions paired with trail cameras across large representative study areas is showing us that parts of Colorado appear to have high lion numbers compared to studies of lions in other states,” noted Viera.

CPW initiated an additional study area in the Book Cliffs north of Grand Junction last winter and plans to begin work in a fourth study area east of Durango this winter.