Western Slope mountain lion density study shifts to area between Bayfield, Pagosa Springs

Dec. 5, 2024

DURANGO, Colo. – Colorado Parks and Wildlife is in its fifth year of the Western Slope Mountain Lion Density Study. After wrapping up study areas in Middle Park and the Gunnison Basin and launching a study last winter in the Bookcliffs near Grand Junction, a new study area will begin this winter in southwest Colorado between Bayfield and Pagosa Springs.

Work on the study in the area between Bayfield and Pagosa Springs will be conducted during the winter months of 2024-25 and 2025-26.

The purpose of this ongoing, rotating study is to get a better understanding of mountain lion populations across the Western Slope of Colorado. Through better understanding of the population density, CPW is able to test its previous modeled estimates and can make even more informed management decisions based on the science.

CPW recently released the results from the Gunnison Basin and Middle Park study areas.

“We’ve already learned a lot from the two completed study areas,” said CPW Area Wildlife Manager Adrian Archuleta of Durango. “Having more data from our area will continue to enhance our local and statewide management of this elusive predator.”

WATCH: Check out this video on the Western Slope Mountain Lion Density Study. 

CPW biologists and field staff will work to put Global Positioning System (GPS) collars on adult mountain lions along with numbered ear tags on each captured animal. CPW will also place numerous remote cameras across the region along with call boxes that attract the lions.

By analyzing images on the remote cameras, CPW researchers can identify mountain lions that have been marked with ear tags versus those without any markers. That relationship between marked and unmarked mountain lions can help CPW get a better estimate of the mountain lion density in the area. The GPS collar data also provides information about how lions use landscapes and how they interact with each other and with human population centers.

“While other mountain lion research projects in Colorado are and have been done to answer a range of biological questions, we are really laser focused on continuing to get a better estimate of the numbers of mountain lions here,” said CPW Southwest Region Senior Wildlife Biologist Jamin Grigg. 

It is CPW’s goal to maintain a sample throughout the duration of the study of 25 collared adult mountain lions within the study area boundaries. The projects are scheduled to take place in the months of December to March when mountain lions and their prey source are on winter ranges.

CPW attempts to cage trap mountain lions when local reports of mountain lion activity come through in a timely fashion. Staff may also use local hound handlers that have dogs bred specifically for tracking mountain lions in the snow. The hounds will try to put a mountain lion up a tree or in a position where CPW staff can dart the animal. While sedated, CPW staff affix a GPS collar as well as numbered ear tags on the animal. Once the collar and tags are in place and a quick examination of each mountain lion is complete, a reversal drug is administered and the animal quickly recovers. The examination helps biologists estimate the age and condition of each mountain lion captured.

CPW is only collaring independent (adult and sub-adult) mountain lions and not kittens.

CPW would like to thank the Southern Ute Indian Tribe and tribal houndsmen for their assistance with this study that will also benefit the Southern Ute Indian Tribe’s Wildlife Resource Management Division.

Landowners and the public can assist in the CPW study by quickly reporting any mountain lion sightings and tracks. To report a mountain lion sighting between Bayfield and Pagosa Springs, call the office at 970-247-0855.

“If people have a dead animal such as a deer in their backyard that just appeared or if they’ve seen a mountain lion that day, we would like to know about it over the next few months,” Grigg said. “That will help us with our capture efforts.”