During winter, most of us in North Central Washington are used to spotting mule deer on local shrub-steppe hillsides, along a river, or crossing roads in our neighborhoods. Some of us wish they didn’t choose to browse on our landscaping! Did you realize that mule deer reside from Alaska to Mexico, all across Western North America?
One reason that mule deer can thrive in so many varied habitats is their ability to be seasonal long-distance migrants. Mule deer follow the same routes, season to season, and year to year. The knowledge of migration routes is passed from parent to young. Locating high quality plant food is the driving force for mule deer annual seasonal migration movements. Deep snow drives herds downslope from mountains to valley bottoms for winter, and keeps them there until the spring melt and the new growth of deciduous shrubs and trees.
Mule deer are browsers and their diet is chiefly the inner living tissues of shrub and tree branches. Cellulose, that forms the cell walls in plants, is not digestible without help from micro-organisms living inside deer digestive tracts. As ruminants, they have multi-chambered stomachs that host microbes to first break down cellulose, and then produce fatty acids that are absorbed by the digestive tract as a source of energy.
Throughout the west, biologists are focusing research to learn about migration routes in order to protect these travel corridors, and minimize human conflicts. Scientists in Wyoming are studying some of the longest and most intact big game migration corridors left in the United States, using GPS tracking collars and camera traps.
Check out their Migration Minute video series, that begins with this captivating sentence: Migrations have been called the heartbeat of the land – pulses of motion between places of life and death. In 2016, Wyoming researchers discovered the longest known mule deer migration route of 242 miles. Watch Migration Champion: What This Deer Does is Amazing!
Western states including Washington, Utah, Nevada, and Wyoming are working to offer solutions to allow mule deer and other wildlife, to safely travel along migration routes where humans have constructed barriers like interstate highways. Watch the 12-minute film, 400 Miles to Cross: The Interstate 80 Wildlife Barrier .
The film is narrated by Gregory Nickerson, a writer and filmmaker who set out looking for answers to how Interstate 80 affects big game herds, and interviewed many experts who have been on the front lines of this issue for decades.
Deer 139 is the conservation-adventure film I’m most excited about- and it is available for free viewing until March 31, 2021 (a COVID silver-lining). It follows three bold women as they follow a single doe’s migration route on foot and on skies, experiencing barriers to migration first-hand.
Biologist Sam Dwinnell conceived the film and assembled the team to produce it, describes it: “This film follows our team of scientists and storytellers as we traced the migration route of a collared mule deer across western Wyoming. It’s a conservation-adventure film that highlights the connections among wildlife, people, and the landscapes they share. Although the film touches on serious challenges we face with wildlife conservation, overall, it is a light-hearted story that is meant to inspire people to get outside and connect with their environment.” Learn more about the film at deer139film.org
Read my next blog post to learn more about North Central Washington’s migratory mule deer. I interview WDFW Biologist, Deven Comstock, to learn about wintering mule deer in the Wenatchee Valley. Wildlife photographer, David Hillestad shares a series of terrific portraits of mule deer he’s encountered in Chelan and Douglas Counties.
To learn more
- The Western Association of Fish and Wild Agencies Mule Deer Working Group webpage has a series of terrific factsheets
- Read the WDFW Washington State Mule Deer Management Plan