October Wildlife Whereabouts: First Snow of the Season

Pronghorn begin preparing for a long migration to their winter ranges outside of Grand Teton.
Pronghorn begin preparing for a long migration to their winter ranges outside of Grand Teton.

Shorter days and cooler nights mean Grand Teton’s wildlife are preparing for the long winter ahead. Many of
the animals have already begun their migrations to warmer climates, while others are settling into their winter
dens in the Tetons.

• Pronghorn generally migrate out of the Jackson Hole valley to the Upper Green River basin near Pinedale. Usually numbering 300-400 animals in the herd, nearly all pronghorn leave the valley in winter; although in some years, small numbers have remained on or near the National Elk Refuge. Last winter’s devastating combination of pneumonia and harsh weather conditions decimated the herd and a minimum of 56 animals were counted in August on the park and refuge, indicating a greatly reduced herd in the valley.

• Elk will begin migrating as November temperatures cool and snow begins to accumulate in the high country.

• Moose have started concentrating in the sagebrush/grassland areas in the south end of the park. They are seeking bitterbrush and other foods in these areas that provide fall nutrition.

• Park mule deer are migrating to distant wintering areas. Those that winter near Cody in the north and south forks of the Shoshone River began their migrations in early to mid-October, while those that winter in Idaho, near Dubois, or near the town of Jackson, migrate later in October or early in November.

• Mule deer coats have now turned from their summer tawny brown to an elegant winter grey, one of the more visible examples of seasonal pelage changes in temperate climate ungulates.

Grand Teton National Park Foundation - wildlife-monitoring-chronic-wasting-disease
Mule deer make their way out of Grand Teton to their winter migration destinations.

• Rough-legged hawks, long distance migrants which spend their summers in the Arctic, usually arrive during November.

• Most black bears and a few grizzly bears will be in winter dens by early November. By the end of the month, most grizzly bears will have gone to sleep as well. But remember, a few grizzlies will be out and about well into December!

• The woods are notably quiet, as most migratory birds have left the valley for their wintering grounds. Gray jays, Clark’s nutcrackers, chickadees, ravens, great horned owls, bald eagles, pine grosbeaks, goldeneyes, and trumpeter swans are a few of the prominent birds that remain here year around.

• Six bat species were common and widespread in the valley, including little brown, big brown, hoary, silver haired, long-legged, and long-eared bats. Bat activity plummeted in mid-September, but a month later long-legged and silver-haired bats were still common, at much reduced levels.

• Native mountain whitefish have just recently begun to spawn in many of the park’s lakes and streams, while fall spawning among non-native brook, brown, and lake trout is about finished for the year.

• As water levels in many streams and rivers approach basal flows, larger fish seek out deeper pools of water to wait out the winter months, often migrating downstream.

• Alpine lakes begin to ice over in October and November, their surfaces remaining frozen until early summer.

• Winter wildlife closures both in and out of the park commence in December, reminding us that wildlife are particularly sensitive to human disturbance during winter.

Wildlife watching is a treat this time of year as animals are often found congregating in and/or moving through lower elevations. Remember to always keep a safe distance and respect our wild animals—if you notice that your presence is causing an animal to change its behavior, stop feeding, or even flee you are too close. On roadways in and out of the park—please be alert, reduce your speed, and watch for wildlife crossing, especially at night and in low light.


Get the latest news right to your inbox!

Looking for more?

Sign up for our featured park happenings, winter adventure ideas, wildlife spotting, and more!

Scroll to Top