07/02/2025
Migration Tracking Week 5 🦌🦌🦌🦌🦌 Deer 665 has arrived on her Teton Pass summer range — and she just turned four years old! In total Deer 665 migrated 173 miles this spring. Her journey required 35 days. That’s including 18 days of travel and 17 days in stopover sites. Clusters of points on June 14-15 suggest she gave birth to her twin fawns, but we don’t have a visual sighting to confirm.
This last leg of migration from June 4-8 really shows Deer 665 determination to get back to her chosen summer range. Instead of staying in the remote Hoback Basin area where she was born in June of 2021 — and where thousands of other deer spend the summer — she followed her usual pattern and pressed on to Jackson Hole.
On June 4, she left Little Granite Creek in the Gros Ventre Mountains. By June 5 she had hoofed it nine miles to upper Game Creek. For orientation, the mouth of Game Creek flows into the Snake River at the south end of Jackson Hole.
Then Deer 665 arrived at the riskiest highway crossing of her entire migration. At about 7pm on June 5, she descended a ridge south of Leeks Canyon and zipped across US 26/191.
This five-lane highway sees 10,000 vehicles a day moving at 55 miles per hour, so she’s truly running a gauntlet. It's a reminder that every time we Visit Jackson Hole or Grand Teton National Park, the animals we see along the highways may have migrated dozens or more than a hundred miles to reach that spot.
Deer 665 reduced the risks by crossing at one of the least developed parts of the highway, where there is a steep ridge on one side and flat irrigated hayfields on the other. This is the same crossing she used exactly a year and a day earlier during her spring 2024 migration.
Though Deer 665 is just one animal, her route is a sign of how this stretch of road and adjacent conservation easements of Jackson Hole Land Trust figure into habitat connectivity in South Park.
Safely across the highway, Deer 665 moved through hayfields and a golf course subdivision before swimming the Snake River a few miles south of the town of Wilson. By June 7, she was in the Bridger-Teton National Forest and climbing into the Teton Range above Mosquito Creek.
Deer 665’s last day of migration was a four-mile jaunt over the crest of the Teton Range, taking her above 8,400 feet in elevation. She passed very near to the site of the June 2024 landslide that shut down the WY 22 highway, which she only missed observing by a few hours.
Finally on June 8, Deer 665 settled into summer range on a steep forested slope a few miles from the Wyoming/Idaho border. Over the next ten days she stayed close to the highway, ranging between 400 feet and 1,400 feet from the road.
Despite the car traffic and noise, Deer 665 knows that this summer range works for her, because she’s returned here for part or all of each summer since 2022.
The exceptional year was her first migration in the summer of 2022, when ventured about 40 miles further to the Kelly Canyon ski area near Ririe, Idaho.
Deer 665 also crossed into Idaho in 2024, but only to a spot a few miles from Victor, before retreating to Teton Pass. This year it seems like she's decided to stay on the pass and not go into Idaho.
Deer 665's GPS route tells us quite a story. We can’t be certain why Deer 665 traveled so far through other suitable habitats only to spend the summer next to the Teton Pass highway. It likely has to do with the availability of food, which is driven by precipitation. As long as there's great food to eat, she doesn't mind the traffic.
Looking at the big picture of Deer 665’s migration, her winter range near Superior, Wyoming is a good place to spend the cold months. That area sees less than 10 inches of precipitation a year and minimal snow cover. But when summer comes, Deer 665 knows where to find lush plants and far better nutrition.
The Teton Pass area that Deer 665 loves so well sees 40 to 60 inches of precipitation each year, thanks to the Snake River Plain funneling in moisture from the Pacific Ocean. (See map in comments.)
Much of that moisture is in the form of the legendary snow sought out by backcountry skiers. Come springtime, the melting snow saturates the soil, causing landslides, but also turning the slopes into a bountiful mule deer garden.
The five feet of precipitation makes Teton Pass rival parts of the Hoback Basin as some of the wettest places in all of Wyoming. And the pass is on par with Wyoming’s best mule deer summer ranges in the snowiest parts of the Wyoming Range, Absaroka Range, Bighorn Mountains, Sierra Madre, and Snowy Range.
All of this means Deer 665 has all the food she needs to put on body fat while nursing her fawns. And that’s a good summary of how she’ll be spending every day from now until the snow flies.
This is the last migration tracking map for this season. Assuming Deer 665 has a good summer, well resume her weekly updates when she starts migrating again this fall.
**In the meantime, however, in the near future we are thrilled to share the back story of Deer 665, which PhD student Luke Wilde only discovered this past January through a fluke of genetic testing.**
In an upcoming post we'll be sharing stories about Deer 665’s birthplace in 2021, her mother, and how Deer 665 became an ultra-long distance migrator, one of only two mule deer we have ever tracked from the Red Desert into Idaho.
Thanks to everyone who has followed along with Deer 665’s story this spring. We hope you have enjoyed learning her part in the amazing world of big game migrations in the American West. We’re wishing you all a happy Independence Day!
The data for this map is thanks to collaboration between our team at the University of Wyoming and biologists with the Wyoming Game and Fish Department, Monteith Shop, Bureau of Land Management - Wyoming, and USGS Cooperative Fish and Wildlife Research Units.
Cartography by WMI's Ian Freeman, based on maps by our Wild Migrations atlas partners at the Department of Geography, University of Oregon.
The Red Desert Mule Deer Study is generously supported by many partners and funders, including:
Knobloch Family Foundation,
George B. Storer Foundation,
Safari Club International Foundation and 100 Hunter Legacy Endowment Fund,
Muley Fanatic Foundation Headquarters,
Muley Fanatic Foundation – Southwest Wyoming Chapter,
Muley Fanatic Foundation Upper Green Chapter
10 Country Chapter of The Muley Fanatic Foundation,
Mule Deer Foundation of Wyoming,
Mule Deer Foundation Headquarters,
SITKA Gear,
National Science Foundation,
Biodiversity Institute of UW – Don and Judy Legerski Fellowship,
Wyoming NASA Space Grant Consortium Graduate Fellowship,
the UW Science Initiative Graduate Fellowship,
USGS Wyoming Landscape Conservation Initiative,
Wyoming Governor's Big Game License Coalition,
Teton Conservation District,
Wyoming Game and Fish Department,
Bureau of Land Management – Wyoming,
The Nature Conservancy,
The Pew Charitable Trusts,
and Sweetwater Royalties, Ghost Town of Superior Wyoming, and Wildcat Coal (for private land access).
