Winter Survival – MFWP
Bruce Auchly, FWP Region 4 Information Officer
Friday, January 15, 2010
Headlines – Region 4
Subzero temperatures and snowstorms are good excuses to stay inside and turn up the heat.
Wildlife, however, doesn’t have that option. Antelope and members of the deer family in Montana have to tough it out. Most do through a variety of methods. But severe winter weather can tax even the hardiest critters.
Big game survive winter through four main adaptations: an insulated coat, reducing their metabolism (up to one-third of what they need to meet basic life functions), remaining bedded for long periods during bad weather and relying on stored body fat.
Up to 30 percent of a deer’s winter energy requirements can be met through body fat. By the way, don’t believe the old hunter’s tale of predicting a winter’s severity by the amount of body fat on a deer, or elk. The amount of fat says more about the animal’s ability to find adequate food in the late summer and fall than the upcoming winter.
“For deer, their condition going into winter is important,” says Tom Stivers, Fish, Wildlife and Parks wildlife biologist. “East of the Divide, elk will go to where ever they can find some grass. And antelope, if it gets really tough, they’ll move to try to find sage and forbs.”
Both mule deer and whitetails will move to find food, too, often to winter habitats the species has used for a millennium. When winter hits the Rocky Mountain Front, for example, mule deer will move down in elevation to ridges and foothills along the front.
The same holds true in the Missouri River Breaks, Stivers says.
Winter represents a downhill slide for big game, even with migrational movements.
“Mule deer on core winter range and habitat will do okay,” Stivers says, “but deer have evolved to lose weight in the winter.”
One scientist likened a deer’s year to sledding on a brushy hill. Through summer and fall the animal climbs the hill, adding body fat. The winter and early spring are the downhill slide. Grass, shrubs and plants can slow the descent, but if the bottom of the hill is reached before spring plant growth starts, the animal dies.
“Elk are big body animals,” Stivers says. “They can eat grass in the winter and get that internal engine running and produce a lot of heat, like cattle. But deer have to process higher nutritional food. So they seek tips of browse.”
Of course plants need to be in good shape going into winter, too, or browse, like willows and chokecherry, won’t have the necessary nutrition.
Deer and antelope and elk do die each winter. Sometimes it’s from age, sometimes it’s malnutrition, and sometimes it’s predators. More than likely death comes from stress caused by a combination of factors rather than just weather.
In fact, an early winter may have little consequence on animals because most have fat reserves to draw on. But as an animal’s energy supply dwindles, usually later in winter, stress factors will start to kill the young, the old and the weak.
One remedy suggested periodically is to feed the deer or elk. It almost always doesn’t work for several reasons. But that’s a topic for another day.
Now it’s time to put another log on the fire.