The long way home: UW researchers tracking lengthy deer migrations

Home|Outdoors Feature|The long way home: UW researchers tracking lengthy deer migrations

SHERIDAN — Anna Ortega couldn’t believe what she was reading.

A Ph.D. student at the University of Wyoming, Ortega had been tracking different migration patterns of the Sublette mule deer herd in the southwestern part of the state. All of the deer had generally followed three routes, migrating either a short distance — 30 miles or less — out of the Red Desert near Rock Springs; a medium distance, traveling about 70 miles to the southern edge of the Wind River reservation; or a longer path, going 150 miles and ending near Jackson.

Except one. Deer 255 had ventured where no mule deer in the Sublette herd had been recorded traveling before: about 242 miles from the Red Desert, ending near Island Park, Idaho. Ortega and the rest of the team began tracking the extraordinary deer in March 2016 and were waiting to see where the deer would end up next. Would it join a different herd and remain near the Island Park area, or head back to the Red Desert, confirming by far the longest recorded migration route in the Sublette herd?

Then the signals on Deer 255 went blank in August 2016. Its tracking collar stopped working and it wasn’t giving off a GPS radar location. The researchers were disheartened, seemingly missing the opportunity to track a unique animal due to bad luck with technology.

Then in March of this year, helicopter pilots working with the Wyoming Migration Initiative found a deer with a brown tracking collar — the same color as Deer 255 — and read its serial number back to members of the WMI. Ortega had memorized the serial number for Deer 255, never totally giving up hope that the animal could still be found. The serial numbers matched, confirming that the long lost deer had been rediscovered.

“I just was so astonished,” Ortega said. “Everyone on the crew was in disbelief.”

“It was pretty exciting and totally unexpected,” said Matt Kauffman, zoology and physiology professor at UW. “We had kind of given up.”

Kauffman also directs the Wyoming Migration Initiative and is a U.S. Geological Survey wildlife biologist. He is overseeing a long-term study that began in 2014 and focuses on mule deer migrating from the Red Desert.

Previously, the longest migration in the herd was about 155 miles, but Deer 255 destroyed that distance when it traveled into Idaho. The UW researchers aren’t completely certain that Deer 255’s Odyssean journey was part of a seasonal migration, but evidence strongly suggests the deer spends its summers in Island Park and winters in the Red Desert.

Deer 255 again appears to the headed in the direction of Island Park. Kauffman said the researchers aren’t sure how many deer make the lengthy trek into Idaho, but the WMI installed cameras in pinch points between Island Park and the Red Desert to see if others are with Deer 255.

The long-term study will continue for at least several more years and should help researchers understand why the animals move in certain directions and how to adjust accordingly so humans and deer can live safely with one another.

Kauffman and his team identified the top 10 concerns for migrating deer in the Sublette herd. They included a bottleneck in Pinedale near Fremont Lake; oil and gas drilling; and the conversion of private land to subdivision construction. The 150-mile route between Jackson and the Red Desert has already been designated as an official migration corridor by the Wyoming Game and Fish Department, which has worked to make it easier for deer to travel without directly interfering with people.

Regarding why deer split up, Ortega said different migration options can be good for the overall lifespan of a herd.

“We’re really starting to understand that a diversity of migration behaviors is maybe beneficial to herd productivity,” Ortega said. “If one of these strategies fails … maybe those other migratory strategies do fine and ensure the productivity of the overall herd.”

In addition to the Sublette herd, there are also large numbers of deer near the eastern edge of the Greater Yellowstone Ecosystem, including the Upper Shoshone, Lander and Dubois herds.

There aren’t any major deer herds in or near Sheridan County, but the animals follow the same general patterns as the larger herds in the western part of the state.

Tim Thomas, a wildlife biologist for the Sheridan region of the WGFD said small herds of animals in lower elevations in the county travel back and forth in short distances, depending on the weather. Thomas added that the movement of animals up and down the Bighorn Mountains is pretty consistent from year to year. Thomas said it is difficult to quantify the exact number of deer in Sheridan County in a given year because they migrate in and out of the county. The wildlife management boundaries aren’t set up by county, either. They are more commonly divided by an interstate or natural features like a river or mountain range.

None of those boundaries prevent animals like Deer 255 from migrating, but the long-term study should provide data to help humans deal better with the traveling wildlife.

By |May 4th, 2018|

About the Author:

Ryan Patterson joined The Sheridan Press staff as a reporter covering education, business and sports in August 2017. He's a native of Wisconsin and graduated from Marquette University with a bachelor's in journalism in May 2017. Email him at:


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