Winters east of Montana’s Rockies are cold, dry and windy. Did someone say windy?
Anyone who has lived through a winter in Montana east of the Continental Divide has a wind story. Usually the story focuses on the wind’s strength or destructive power, such as knocking over a tree or an 18-wheeler. Sometimes it’s funny, but often not so.
Because organisms are shaped by the environment in which they evolve, our weather over eons gave us vast tracts of grass-filled, mostly treeless prairie populated with plants and animals able to withstand the extremes of winter.
Some animals, such as bison, use strength and size to deal with winter. To find food, bison will swing their massive heads side to side, plowing through snow to expose grasses. The animals’ thick, dense hair gives the species both insulation and a thick coat to handle abrasion from plants like sagebrush.
For a smaller prairie winter survivor consider the antelope, pronghorn if you prefer. Where a bison will tip the scales at 2,000 pounds, a full-grown, male pronghorn might run 150 pounds.
Because they are not built to move deep snow to eat grasses, pronghorn feast on taller sagebrush plants. During the winter, sagebrush can make up more than 80 percent of their diet, and the animals will move scores of miles, if necessary, to find it.
Birds that thrive in the harsh prairie winter are specialists probably helped by a wind that moves snow across the prairie floor. Some look for seeds; others seek prey species.
Drive any prairie gravel road now and you may find and scatter a flock of small, drab birds. Those little brown, white and black creatures are usually snow buntings, feeding on weed and grain seeds.
Two avian predators fly to Montana in the winter from more northern habitats: the occasional snowy owl and
the regular rough-legged hawk. How about that – a pair of birds that think our prairie winters are down right balmy.
The mostly white snowy owl, with a wingspan of five feet or more, makes its home on the Arctic’s treeless expanse. Yet periodically, when its food (mice and lemmings mostly) becomes scarce, some owls fly south often to areas that resemble their tundra home. Enter the prairie.
The most visible and common winter raptor may be the rough-legged hawk. The rough-legged hawk nests north of us, from Alaska across Canada. By November it has moved south to patrol Montana’s prairies, searching for mice and small animals. Come March, it returns north.
Of course, what wind removes, it can also create. Snowdrifts provide hideouts.
Several years ago, I watched a Hungarian partridge barely escape a determined a gyrfalcon, the largest falcon and a rare winter visitor to Montana, by diving into wind-driven snow piled against a small shrub.
Whew. Death and a meal took a pause that day.
For us, wind has benefits, too. I kid you not. Chinook winds that barrel down the Rocky Mountain Front can turn a spell of deep snow and cold weather into a cleaner, milder, brighter stretch of winter.
Life and death, wind and sky, all make then remake the prairie landscape into a thing of beauty.
- By Bruce Auchly – Montana Fish, Wildlife, and Park; Tales and Trails is a regular natural history column produced by FWP Region 4
