People, Parks, Pumas and Prions

The puma, or mountain lion, ranks as Colorado’s top predator and one of Rocky Mountain National Park’s most charismatic species. For more than a decade park managers have wanted to conduct research on this elusive animal: How many of these big cats live in the park? What do they eat? Is the population stable or declining? Is the park a source of cat immigration into nearby Boulder County? Are there safety concerns that aren’t being addressed? And recently, the question arose to whether these big cats prefer deer that are infected with chronic wasting disease (CWD), a deadly disease spread by malformed proteins called prions. That is, do mountain lions selectively prey on infected deer and act as a natural control to the spread of the disease, a behavior that would support the old theories of natural selection. These are but a few of the questions that will be answered over the coming years as researchers, led by the Colorado Division of Wildlife (CDOW) and USGS-Fort Collins Science Center (FORT), begin to reveal the ecological story of the Park’s most impressive and least understood resident.

Even under the best of circumstances, research on mountain lions is difficult. It takes a sizeable budget, a qualified and motivated team of specialists, and a considerable amount of time. These cats do not give up data easily. They evolved over the millennia to thrive in low numbers over vast areas. Their genetic code guides them to blend into the landscape, making detection difficult even for the trained eye. Most experts agree that about seven years is the minimum time to adequately study a mountain lion population, but only a handful of studies have ever gone that long. Cost and time commitment is why mountain lions have never been studied in Colorado’s Front Range, including the Park area—until now.

Rocky Mountain National Park managers engaged FORT scientists to study mountain lion ecology in the Park, and the Division of Wildlife is spearheading a study to determine the role of mountains lions in the spread of CWD. The DOW study calls for testing lion-killed mule deer for CWD, while the Park study investigates all aspects of mountain lion ecology: birth and death rates, movement, home range, population dynamics, and mountain lion-human interactions. Given the daunting amount of field work, including capturing and monitoring up to twenty-six mountain lions in the Park and the northern Colorado Front Range, a research alliance was welcomed by both agencies.

Our joint research team started on a historic note with the capture of a large male on the McGraw Ranch, a former dude ranch that is now a Park research station. We named the cat “Frank,” after the former owner of the ranch, Frank McGraw. The first mountain lion ever captured in RMNP, Frank was fitted with a radio collar in February 2004 and we have monitored his movements ever since. He has moved south to Moraine Park, west to Endovalley, east to Glen Haven, and north to Fox Creek—a home range of approximately 100 mi², with a core area of approximately 70 mi². Since Frank’s movements show that he is a resident cat, in April 2005 we replaced his less accurate radio collar with one that collects global positioning system (GPS) locations so that we can track him more precisely, locating kill sites and monitoring reproduction events. It took more than a year to recapture him, in part because of the divergence between park mission and the use of trained hounds inside the park, the most common and effective method for capturing mountain lions.

A second capture occurred in October 2004 in Black Canyon on the MacGregor Ranch, not far from the McGraw Ranch. Using a leg-hold snare, we caught “Muriel” (named for the original Mrs. McGregor), a healthy adult female. Presuming Muriel to be a resident cat, we fitted her also with a GPS collar. Her movements have led us to many kill sites within a home range of approximately 30 mi² and a core area of about 15 mi². Of the kill sites we located, Muriel seems to prefer elk and mule deer, with an occasional raccoon.

We monitor Frank and Muriel weekly. Over time, if nature takes its usual course, Muriel will rear cubs that will help determine sex ratios of kittens, survival rates, immigration patterns, and other life history data. All events and fieldwork data are entered into databases that feed into computer models. These models are designed to analyze and predict potential mountain lion distribution and strengthen future management activities at the Park, in Colorado, and in other national parks throughout the West.

Early on, we learned that the Park’s mountain lions do not confine themselves to the interior of the park, especially on the east side. This became obvious as our study cats regularly used the property of larger landowners in the Estes Valley, such as the MacGregor Ranch where Muriel was captured, the Lost Antler Ranch, and Eagle Rock School. The associated landowners have been very helpful, lending support and access to their property and sometimes volunteering in the study. These properties and others play a vital role in supporting the park’s east side mountain lion population, and the research team greatly values landowners’ input and cooperation.

Tests of non-invasive tools such as camera traps, call boxes, and DNA analyses are also part of the Park’s research project. These tests will help determine the comparative value of invasive versus non-invasive tools for monitoring mountain lions. If non-invasive methods prove successful, it may not be necessary in the future to physically capture mountains lions for effective population assessment. Most of the testing has focused on a combination of baiting with deer carcasses, call boxes, and new camera traps, including a self-triggering, digital-video setup. Using the video camera, we filmed hours of mountain lions and other predators feeding at a bait site. We experienced some success also with “calling” cats to bait sites and to camera traps, using a speaker that sends out loud prey species distress calls. These new tools show promise, and continued testing will evaluate their net effectiveness for future monitoring.

Also, we are collaborating with colleagues in South America and central Asia who are studying mountain lion, jaguar, and snow leopard. The research is similar in that we are all striving to learn about a secretive feline faced with diminishing habitat, and are devising novel research approaches to include new but at times unstable technologies. Through continuous information sharing, success in any of our studies enhances big-cat research in other parts of the world.

Though we are a long way from being able to make sound conclusions on mountain lion ecology, our multi-agency team has made significant progress. We will continue to work with park management on tests of non-invasive capture methods and possible use of trained hounds. Over time, as we closely follow our radio-collared cats, they will “tell” us where they live, what they eat, and how they interact with Front Range residents and Park visitors. With this information, Park managers can better understand and manage this key predator and educate the public to protect both people and pumas in and around Rocky Mountain National Park.

Colorado Mountain Lion Research Group
Living in Lion Country
Mountain Lion
Chronic Wasting Disease

Don O. Hunter
U.S. Geological Survey
Fort Collins Science Center
2150 Centre Ave. , Bldg. C
Fort Collins , CO 80526-8118
970-226-9382
don_o_hunter@usgs.gov

Caroline Krumm
U.S. Geological Survey
Fort Collins Science Center
2150 Centre Ave. , Bldg. C
Fort Collins , CO 80526-8118
970.226.9450
caroline_krumm@usgs.gov

People, Parks, and Pumas... and Prions

A Multi-Agency Partnership Brings Mountain Lion Research to the Colorado Front Range