Monday, March 05, 2012

Wild Colorado: Tracking tracks in the snow

A set of tracks zigzags across the slope below the chairlift, seemingly random and haphazard.
They backtrack on themselves, seem to cover little to no ground and are dotted here and there with snow disturbances, like something was digging or just stuck its head in the snow.

These are likely fox tracks, says Dan Eberle, the youth coordinator at Friends of the Dillon Ranger District, a nonprofit that works on the ground alongside the Forest Service. The organization coordinates volunteers to do trail work and education that Forest Service officials aren't able to do due to funding priorities.

They look lost, Eberle said about the fox tracks. But they're really listening and smelling for subnivean creatures such as mice and voles that rely on winter snow cover for survival. Such creatures move under the snow, where, when it's deep enough, it remains a constant 32 degrees regardless of the temperature above snow. Subnivean is the term used to describe the zone just under the snow from the Latin for under (sub) and snow (nives).

Fox and owls can hear their prey through the snow and pounce from above, said Eberle.

Those are the variable holes amidst the tracks.

When you see disturbances in the snow, that's where fox jump in and pound through the snow. Sometimes they stumble on a nest, Eberle said.

Different tracks, different stories

Fox are less aggressive hunters than the more elusive ermine, a type of short-tailed weasel that storms nests of critters and demolishes them, Eberle said. He's once spotted the white weasel with its black tail only once, but it was early in the morning as he trekked to the top of Keystone's snowy slopes before the resort opened. Rarely, if ever, has Eberle come across the ermine's tracks.

Different tracks tell different stories, said Eberle, who partners with Daniel Rudolf on Fridays at Keystone Resort to guide visitors and locals on an hour-long, free interpretive tour of Summit County's snowy environment.

For instance, a pine squirrel doesn't like to stay on the ground long, so its tracks are quick, running from tree to tree.

Typically, snowshoe hare prints are tucked close to trees, which they use for cover.

As prey, both animals look to their various habitats for safety when they're not out foraging for food. Sometimes, a predator's tracks can run alongside its prey, which tells the story of a hunt and possibly a kill.

Often, Eberle finds it interesting to point out that snowshoe hare tracks represent movement in the opposite direction from which they appear. The larger hind legs land in front of the smaller front legs, he said. It's intuitive to think the larger hind legs would be behind the front legs, and that fools fellow creatures as well as humans.

Their tracks send mixed signals and deceive predators, Eberle said. It's not something they do on purpose, obviously, but said it's a type of biological confusion that's part of the natural environment.

Deer and elk tracks aren't as common in the High Country in winter, because the large game animals typically migrate to lower elevations where food supply is more prevalent. Otherwise, they're burning more energy than they're taking in, looking for food, Eberle said. Moose tracks could be more common, but it's not likely to see them at the ski resort, as they're more solitary creatures that live near wetter drainages.

It's easy to see some tracks from the chairlift, but Eberle and Rudolf's Ski With a Ranger Program and similar programs at Copper Mountain and Breckenridge Ski Resort get skiers to slow down and take a look in tree islands for tracks elsewhere on the mountain. Sometimes, animals and humans look to the same lines for travel, too. Skiers who pop into the trees often come across animal tracks that run the length of the line they're looking to ride.

Though feline and canine tracks aren't common at the resort, Eberle noted their major differences for those hiking or traveling in the backcountry: Feline claws can retract while canine claws don't.

So, if one comes across a large, roundish, fist-sized print without claw marks, it's likely a mountain lion's track. A smaller print with claws that's longer rather than wider, and more oval-shaped could be a coyote or a domestic dog.

Take a minute next time you're out and look around you just might stumble across an animal's tale in the snow.

More info:

Learn more about animal tracks in winter through Friends of the Dillon Ranger District's Ski With a Ranger program, which runs at 11 a.m. Fridays at Keystone Resort, Breckenridge Ski Resort and Copper Mountain.

Call (970) 262-3449 (970) 262-3449 , email or visit for more information on the tours.

Friends of the Dillon Ranger District also offers similar interpretive tours in summer, which can showcase an entirely different realm of High Country wildlife. Look to the website for the upcoming schedule.

Courtesy Summit Daily News