Get Wild: Turning white in winter
Summit County looks great in its new coating of fresh white snow! In winter we can enjoy snowflakes falling, skis sliding and mountains gleaming bright white, contrasting with our beautiful blue skies. While we are watching the snow falling, some of our year-round residents are changing colors to match the white: ptarmigan, snowshoe hares and two species of weasel. This strategy helps the predators to blend into the snow and sneak up on their prey, and for the herbivores to hide from their predators.
Above timberline in our mountains lives the elusive little white-tailed ptarmigan, Lagopus leucura, the smallest member of the grouse family in North America. Famous for blending into the tundra, summer and winter, ptarmigan are the only birds in the world that turn white in the winter. Their winter colors are pure white except for the dark eye and bill. Fluffy white feathers cover even their feet, keeping them warm and acting like snowshoes. With spring snowmelt, ptarmigan gradually replace winter feathers with speckled pale and dark brown, blending in with summer tundra rocks and plants, while they nibble on pieces of plants. Their diet consists mostly of the buds, leaves and twigs of low-Alpine plants. The tail is white year-round, distinguishing them from other ptarmigan species.
Other ptarmigan species are found farther north in Canada and Alaska. The white-tailed ptarmigan also lives up north, as well as in the high mountains of the Rockies all the way down to northern New Mexico. Even though ptarmigan are masters of blending in with the tundra, they are not as common in Colorado as they used to be, likely because so many recreationists travel above timberline. Dogs not kept on leashes are especially problematic because ptarmigan are ground nesters.
The snowshoe hare, Lepus americanus, is a classic winter mammal in Summit County, with snowshoe feet ready for snow anytime. They live at high elevations where large feet are practical year-round, and then acquire a thicker, pure-white coat during winter months for additional winter warmth and camouflage. The snowshoe hare may have up to four litters in a year, which average three to five young. Males compete for females, and females may breed with several males.
The endangered Canada lynx is a major predator of the snowshoe hare, and the population cycles of the two species are closely linked. I saw snowshoe hares in my backyard every year for over 20 years, but in the last two years, I have seen only cottontails. Sadly, there’s evidence that climate change, which is reducing our snowpack, is causing reduction in snowshoe hare populations. Without the protection offered by deep, long-lasting snow, snowshoe hares suffer increased predation by coyotes, bobcats and other predators, while our lynx lose their competitive advantage.
The short-tailed weasel, Mustela ermine, and long-tailed weasel, Neogale frenata, are both in the Mustelidae, or weasel, family. Known for being ferocious predators, these tiny weasels commonly attack much larger animals. Extremely fast and efficient predators, they can leap quite high, pouncing down on prey under the snow. Unlike ptarmigan and snowshoe hares, these weasels maintain a black tip on the tail. Why? It’s thought that this wildly whipping black tip provides a distraction to predators. Weasels are quite elegant animals, and it’s fun to spot them in our Summit winters. They move so quickly, but that black tip is eye-catching. I had the pleasure of seeing an ermine last winter, right out my backdoor after catching a chipmunk in his mouth.
As you admire our magnificent white mountains, you may also get lucky enough to see one of our masterful white camouflagers living nearby.
Karn Stiegelmeier is the chair-elect of Eagle Summit Wilderness Alliance, an all-volunteer nonprofit that helps the U.S. Forest Service protect and preserve the wilderness areas in Eagle and Summit counties. For more information, visit EagleSummitWilderness.org
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