The Wildlife

In the Boise River drainage elevations range from over 10,000 feet down to 2,200 feet at the confluence with the Snake River. Forests in the higher mountainous regions can receive 30-60 of annual precipitation. In the lower semi-desert elevations portions of the basin averages about 8-10” per year.

Photo Credit: Scott Rudel

The wide range of elevation, precipitation and vegetation – from desert to alpine – means a wide variety of wildlife can live in the drainage. Some, like mule deer and elk, live in the basin year round while others, such as migratory birds, come here for part of the year.

Mule deer and elk spend their summers scattered throughout the drainage. As winter approaches they migrate to lower elevations where snow doesn’t get as deep and temperatures are not so cold. About one-third of the approximately 25,000 mule deer in the drainage migrate to the Boise River Wildlife Management Area (WMA). Nearly a thousand elk also call the WMA their home during winter.

Mule Deer Group

Photo Credit: Scott Rudel


Boise Mtn Elk Herd

Photo Credit: Dirk Vandervoort

Migration Routes

For generations deer herds have migrated from as far away as the Sawtooth Mountains to as far south as the Deer Flat Wildlife Refuge. Their off-spring continue to follow the same routes with one exception. Deer and elk now stop short and winter in the Boise Foothills.

Today roads, railroad tracks, reservoirs, fences and cities lie directly in the path of their historic migration route. In the case of the City of Boise, the town and housing developments are built on much of their historical winter range.

Elk Snow Ridge

Photo Credit: Scott Rudel

When the snow flies in the mountains, upwards to 8.000 mule deer and a thousand elk move toward the Boise Foothills They follow the ridgelines and draws, steadily moving down hill and down river. Come spring deer and elk use the same trails to return to their summer range in the mountains.

During both migrations, elk and deer cross Highway 21 at least once. When bad winters drive wildlife down to the Boise River, they will frequently cross Warm Springs Avenue, as well.