Study offers insights into mountain lion populations in Colorado’s Western Slope

DENVER (KDVR) — A multi-year study conducted by Colorado Parks and Wildlife of the population density of mountain lions in the Western Slope has revealed healthy numbers which have even exceeded projected estimates in some areas.

The approval of the West Slope Mountain Lion Management Plan by the Parks and Wildlife Commission in 2020 spurred the study which began in Middle Park, the area between Kremmling and Granby, in the same year. The study expanded to a second location in the Gunnison Basin in 2021.

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"These study areas were selected to be representative of Colorado's lion habitat with balanced habitat types, landownership and lion harvest levels," said Mark Viera, Carnivore and Furbearer Program Manager at CPW.

The subject of the study was to record an estimated number of independent adult and subadult mountain lions in various areas and habitats within the Western Slope.

CPW deployed a team of wildlife biologists, district wildlife managers and researchers to mark, collar and monitor mountain lions in these areas. They collared a total of 98 mountain lions with 48 monitored in the Middle Park study and the other 50 in the Gunnison Basin study.

"We were 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," said Vieira. "Data confirmed that current management is meeting agency goals of providing opportunity while managing for healthy and robust populations."

The CPW staff spent hundreds of hours accumulating data over the course of two years. To watch the behind-the-scenes of how CPW worked with locals to perform the study of Colorado's biggest cats, visit the Colorado Parks and Wildlife YouTube page.

A CPW biometrician analyzed the biological data from the study and estimated the number of independent mountain lions in Middle Park during the winters of 2021-2022 and 2022-2023 and the same metric in the Gunnison Basin during the winters of 2022-2023 and 2023-2024.

Middle Park: 2.5 independent mountain lions per 60 square miles

Gunnison Basin: 4.2 independent mountain lions per 60 square miles

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Trail cameras, ear tags and GPS collars allowed CPW to track the amount of marked mountain lions and unmarked mountain lions in an area during the "resight phase" which is processed through a mathematical model that gives a total estimate of the mountain lions in the area.

The data allows CPW to have a deeper understanding of population density when determining the management systems of the big cats.

"These results show that the lion populations in these representative study areas are strong," Vieira said. "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."

After finding success in these initial studies, CPW conducted a third study in Books Cliffs north of Grand Junction during the winter of 2023-2024 and will begin a fourth study this winter in the area just east of Durango.