A season-by-season look at animal survival in the mountains

Matt Terrell
April 23, 2008

There might be thousands of deer in Eagle County, but somehow, spotting even one never seems to get old.

Diane Berger says she’s rarely been on a camping trip without running into something fascinating, something wild, something just a little bit scary, like the bears that sniff around her tent at night or some bizarre insect. She enjoys seeing marmots near tree line and large birds hovering in the sky.

Morgan Cushing says he sometimes sees a fox — or maybe it’s a coyote — dash across his driveway in Eagle-Vail when he comes home at night.

The briefest glimpse of a wild animal is exciting, even for locals who are used to it, he says.

For most of us, though, our intrigue with wildlife begins and ends with those personal encounters. We’re not wildlife scholars — just pleasantly amused and a bit in awe of all the creatures in our backyard.

Behind the scenes, however, there’s more going on than we realize. Animals here have adapted in interesting ways to survive the drastic changes in the mountain environment, says Craig Wescoatt, a district manager with the Colorado Division of Wildlife.

It’s easy for us, but living here is a struggle for them.

Spring
One of the first scientific concepts you become aware of as a child is that spring is a time of renewal.

It’s quite a visual transformation here, where we watch the snowline crawl up the mountains, ground squirrels pop out of their holes and green return to the aspens. What once looked dead, white and barren begins to take color and fill up with life.

You hear the change when birds that have been long gone for months return with chirping and song. Bald eagles, which live here during the winter, head back north, while other birds that migrated to Arizona, New Mexico and Texas for the winter return for the summer. Other birds, like sage grouse, may only move half a dozen miles for winter.

“We have hummingbirds coming back from Central America or South America — that’s a heck of a long way,” Wescoatt says.

Male birds return first, establish territories and hope to attract females, who will soon arrive to do a bit of shopping. They’ll choose whoever has the nicest digs — homes that are safe, won’t get too hot, won’t get too cold and have plenty of nearby food, says Tom Wiesen, a longtime wildlife observer and owner of Trailwise Guides.
“They’ll choose the place that will give them the best chance of raising a successful brood,” Wiesen says.

Soon, you’ll hear the drumming of Williamson’s sapsuckers, a type of woodpecker.
Male sapsuckers rap their beaks in intricate patterns on dead trees that reverberate through the land and attract females. Male sapsuckers also burrow small cavities into several trees, and females fly by and check them out, eventually choosing the best ones to nest and raise young in, Wiesen says.

If they mate, the female will lay eggs, and the male will bring food back to the nest. Sometimes, they’ll trade places.

Most deer and elk are now in their last stage of pregnancy, with most of the young being born between the middle of May and June, says Division of Wildlife manager Bill Andree. If you happen to come across baby deer and elk, leave them alone. They don’t like humans, and will spend a lot of much-needed energy trying to get away.

Bears start showing their faces as early as March, with most coming out by mid-May. By this time, they’ve already had their babies, which are born in December in their winter dens.

Larger animals, like deer, bears and elk, let their young stay with them for a year. For smaller animals, like rabbits and birds, they’re on their own by summer, Wescoatt says.

Summer
Animals and humans share an obsession with fat.

While humans spend their entire lives figuring out how to lose weight, animals base their existence on weighing as much as possible. Every second of their lives is spent in preparation for winter, and surviving winter means putting on the pounds.

It’s interesting to think of this in the summer, when food is most abundant, when animals are rearing their young and storing energy for the winter. When you see a deer, bear, bighorn sheep, coyote or mountain lion, they’re not just eating. They’re trying to get fat. All this food won’t be there in the winter, so they have to store it in their bellies.

This is how humans traditionally have survived — we’ve always gathered food when it was most abundant and easiest to find and found ways to preserve it for when it was more scarce, thus explaining the existence of jerky, salt pork and pickles.

By summer, animals that had moved to lower elevations during the winter move back up the mountain, where they can take advantage of the abundant grass growing in alpine meadows. It’s also much cooler at 10,000 feet, and cooler means fewer calories being burned.

Some animals get fat, and other animals start storing food to survive the winter. Take the pika, a small member of the rabbit family that lives in cool alpine rock fields called talus. You’ve probably seen one while hiking near timberline, scurrying from boulder to boulder then ducking to his safe shade below the rocks to hide from birds of prey and the hot afternoon sun.

They have furnace-like metabolisms, don’t shed their fur, thrive in the cold and will actually overheat in crisp, 75-degree weather. Since they don’t hibernate, they spend much of their day during the summer scampering around boulder fields, collecting enough flowers, leaves and grass to dry and store in hay piles hidden under the rocks. During the winter, that hay pile will keep them from starving.

Fall
Fall is sort of the opposite of spring for animals. Birds start flying away, it gets colder, and animals start to panic. This is it. Winter is around the corner, and if you aren’t fat enough, you will die.

We see this panic most visibly in bears. Before winter, bears go into 20-hour-a-day feeding frenzies, which makes them quite troublesome for us, as they often head for our Dumpsters to find easy food.

“They’re frantic to put on weight,” Wescoatt says.

For male elk, putting on all that weight during the summer helps prepare them for breeding in the fall. A species survives by ensuring that the strongest, most dominant animals breed to pass on the best genes, and dominance can either be established the easy way, or the hard way.

The easy way? Animals that look the biggest, the baddest and the strongest get to breed, and the others don’t, Andree says. The bigger your antlers, the more dominant you are.

“If you’re a 98-pound weakling in the wildlife world, they’ll kick sand in your face,” Andree says. “If you’re the big strapping guy, they won’t pick a fight with you.”

If you can’t establish dominance with size, big antlers and loud calls, the alternative is to fight, which is tiresome, wastes a lot of energy, and is often deadly. Mother Nature sets it up so the animals usually don’t have to head into a bloody battle, but sometimes, it happens, Andree says.

Winter
We may hate driving over Vail Pass in the winter, but it’s not quite the struggle for life that animals face.

Winter, no matter what animal you are, is the most difficult time of the year. Wescoatt says he can’t think of an animal that actually thrives in the winter as opposed to another season, and naturally, a lot of animals always die in the winter.
Still, they find their own unique ways to survive.

Some animals, like marmots and ground squirrels, hibernate in the winter. Like clockwork, their bodies shut down when winter comes to conserve energy. Their body temperatures drop to 10 degrees above freezing, and they won’t wake up until spring. If they have enough fat, they’ll survive. If not, they’ll die.

Animals like bears and beavers don’t enter a true hibernation, but they go into a state that’s sort of like hibernation, but allows them to wake up, defend themselves or find food if needed.

You could pick up a ground squirrel, shake it, and it wouldn’t wake up while it’s hibernating. Poke a bear hard enough in the winter, and they’ll start moving, Wescoatt says.

Most animals don’t hibernate. Some birds, like hawks, stay here during the winter and feed off rabbits and mice. Luckily, they don’t have to deal with the deep snow like other animals do.

Traveling through snow is a pain for most animals. During winter, it’s essential that they use as little energy as possible, and as you probably know from your last hut trip, walking through snow is exhausting. It burns too many calories for an animal that’s basically starving for the entire winter.

That’s why most animals move to lower elevations during winter, where it’s a little warmer and there’s less snow.

“If I’m on a starvation diet, I’m going to the place with there’s the least amount of snow possible, where I don’t have to walk as much, where it’s easier it is to find food,” Andree says.

An exceptionally snowy winter led the Division of Wildlife to feed deer for just the third time in nearly 25 years this past February. All that powder may be great for the ski slopes, but it covered up the small plants and shrubs, like sagebrush, that deer eat in the winter. Many deer, seeking mountain valleys where they’ve found food in previous winters, ended up finding almost nothing this year and were often trapped in those valleys by towering snow drifts.

The Division of Wildlife will only consider feeding animals if there’s a chance more than 30 percent of adult female deer will die in a winter.

Many female animals are pregnant through the winter. A healthier mother usually means a healthier baby, and really, that’s how a species survives.

“When you need to pass on genetics, you do that by having successful young,” Andree says. “If you pick a good place to live where there’s lots of food, the mother comes through winter in good shape, and her offspring will have a better chance.”

And then you come back to spring, when you see who died, and who gets to do it all again.

Staff Writer Matt Terrell can be reached at 748-2955 or mterrell@vaildaily.com.