Dave Hallock, Eldora.   The diets of mountain lions (also called cougars or pumas) change from almost strictly deer and elk to include a higher amount of smaller prey, including raccoons, skunks and domestic animals, as a landscape becomes more developed and a human presence increases. But overall, the lions that inhabit the northern Front Range spend most of their time in areas that have few to no homes, are away from roads, and are forested. This is some of the information being gleaned from the 10-year Front Range Cougar Study.

Few studies of mountain lions have looked at how they are living in the urban-wildland interface - their movements, food habitats, age structure, and interactions with other animals. Dr. Mat Alldredge of Colorado Parks and Wildlife gave a presentation to Boulder County this winter on some of the preliminary results of the study, which began in the fall of 2007 (the presentation is available at https://youtu.be/Ieie9f6qZy8 - it is about 1.5 hours long). The study area ran along the east side of the Front Range from Lyons south to I-70. One hundred and two independent cougars were captured and fitted with GPS-collars over the ten years, which provided their locations eight times a day.

We all know some mountain lions use urban areas. They tend to come into urban areas, like Boulder, at night looking for prey, and generally finding small prey, which are easier to catch and carry away for eating, or meeting the needs of cubs. The adult lions that come into town are often young, and more commonly females, particularly females with cubs likely hanging out on the edge of town.

As lions age, they increasingly spend time away from homes and roads. Overall, they disfavor developed areas, roads, and open areas. This is the opposite of where people generally encounter them, which are around homes, along roads, and/or in open areas. But they have large territories, can travel long distances, and are opportunistic when finding prey. Where we see them does not tell the whole story.

In June and July mountain lions have their lowest presence in developed areas, as they head to more rural and undeveloped areas where deer and elk are fawning. Ungulate calves become an important part of a cougar’s diet in late spring and summer. Overall, adult mule deer are still the most important prey species throughout the year and they will also take elk.

There is a known killing of an adult moose in Larimer County, and moose are a regular part a lion’s diet in Canada. But taking a moose is a lot of work (though high reward) with a high risk of injury.

The killing of a deer or an elk by a lion provided an additional research opportunity. A lion can come back to a kill site for one to two weeks, so the GPS locations will stay in a fairly small geographic area. Researchers would go looking for the kill, and if found, placed cameras around it. They witnessed some sharing of kills with other lions, but not much. Mostly, other animals that can scavenge meat might share the kill, particularly bears. Sixty percent of the lion kills that were monitored with cameras were taken over by bears.

There were a number of other findings from the study. The main activity time for mountain lions is dusk through dawn; they are not very active during the day. They are fairly solitary animals and don’t spend much time together, except for a mother with young. Their estimate of population, using methods that included analyzing DNA from hair snags, is between 30 and 55 lions along the eastern side of the Front Range between Lyons and I-70.

Dr. Alldredge didn’t feel that lions got “habituated” to the prey resources found around people, but are mostly just opportunistic. He cited one lion that grew up outside of Boulder, and would come into town, then moved west and there were no incidents for a few years, then it took some livestock near Nederland, avoided capture, then went to Heil Valley Ranch area near Lyons for a few years where there were no problems. She lived to an age of 10.

Mountain lions can move long distances. One collared animal moved north to central Wyoming while another headed south to southeast New Mexico. New adult males tend to disperse the furthest. New adult females tend to first wander, but may come back to live in the same general area where born. One adult female came into the study area from South Dakota.

Lions were hunted for a bounty in Colorado until 1965, and it is likely that their population was much lower before removal of the bounty. But there is still mortality and most mortality is related to human activities. There were 56 mortalities of the 102 animals collared over the 10 years. Fourteen were roadkill, 21 were human interactive (owner or agency kills animal due to problematic behavior from a human perspective), and 7 were hunted. Four of the mortalities were of one lion killing another - 1 male and 3 females died this way. Four mortalities were natural, such as getting killed during the act of trying to take down an elk.

Following are some of the June nature happenings in the Nederland area. The last of the migrating birds will arrive in early June, these being Swainson’s Thrush, Cordilleran Flycatcher, Western Wood-pewee, and Black Swift. While hiking up the trail to Arapaho Pass, take a look over to the water fall on the opposite hillside that comes out of Diamond Lake; a small colony of black swifts nests behind the falls. You may see the swifts hunting for insects above the valley. Clark’s Nutcrackers will already have young-on-the-wing, flying around in boisterous flocks.

Elk are calving. In late June and into July they will move up into the Indian Peaks. Moose generally calve in late May and early June. Short-tailed weasels (ermine) give birth in May, June and July. Pine squirrels are born from mid-May through mid-July. Marmot young emerge from their dens beginning in late June.

Butterflies can make a strong showing. Look for orange-tips, small white butterflies with bright orange tips, patrolling up and down canyons. Large swallowtails begin emerging, the beautiful tiger swallowtails generally found around willows and aspen.

Common ringlets, common alpines and chryxus arctics are seen flitting in meadows. Parnassians, large white butterflies with black and orange spots who stay low to the ground, also emerge in meadows in June, often tied to the blooming of their host plant, stonecrop.

Common meadow flowers for June include larkspur, golden banner, wallflower, and mountain parsley. Plants blooming on the tundra are found in areas uprooted and disturbed by pocket gophers, including mertensia, sky pilot, wallflower, alpine lily, and old-man-of-the-mountain. Pine trees produce lots of pollen throughout June: aaachoo!