There is no great metaphor for migrations — fish, bird, insect or mammal alike. A river? It only flows one direction, shackled by the cuffs of gravity. A current, like the wind? But winds are usually prevailing from one cardinal direction or another.
Migrations are flows, bound to the rhythms of the Earth, the turnings and tiltings of the globe, the rays and shadows of our great sun’s life-giving or life-taking light across this little blue marble.
One thing is certain, the mechanics of migrations, particularly of our treasured and beloved big game, were once largely unknown by modern man. Invisible. We knew they were there, but we did not know much about how they got there or about their journey.
Thousands of years ago, mankind was more attuned to these things, perhaps. Wyoming is awash with the record of this knowledge. Great buffalo jumps where the colossal beasts were piled up in heaps and butchered on the spot, sheep traps in high-mountain holds, kill sites used again and again by generations. We think of our traditional hunting camps as heirlooms, passed from one generation to the next over time, camping and hunting in the same place great grandpa hunted in the 1930s. In our modern world, there are few 100-year-old hunting camps, but in the Early Archaic Period those places lasted 3,000 years and more. That is the very definition of legacy.
Atop a nondescript sagebrush bench separating the Green River from the New Fork River a touch west and north of Pinedale is one heck of a heritage hunting camp. Here, at Trapper’s Point — named for the famed fur trappers who came into the country thousands of years behind the early hunters — archaeologists have unearthed the ancient story of hunter and hunted, a tale of migrating prey and calculating predator intersecting at a pinch point on a great game migration route that has existed, and still exists, for thousands of years. The Trapper’s Point dig has revealed evidence that early hunters routinely killed migrating pronghorn in the spring of the year, starting at least 7,000 years ago.
Of course, early man and his atlatl and the bearded fur trapper with his muzzleloading rifle are long gone. But the migration, with all the challenges created by modern mankind, continues. Today, despite highways, fences, oil and gas fields, subdivisions and reservoirs, the current still flows.
A new age
Perhaps no other science has benefited as much from technology and social media as the study of big game migration. GPS collars with good battery life, game cameras, digital cinematography, GPS mapping, DNA analysis all blossomed in recent years, and the story derived from these tools has flourished in living color on social media.
Observers of the natural order of things have long known about the cadence of big game on the land, chasing green-up away from the winter range into early spring, moving into the high country to summer, climbing sometimes to the very tops of Wyoming’s highest peaks. In the fall, driven by snow or perhaps hunting pressure, dropping into the low country, moving down ridgelines into valleys, wintering where the state’s famous winds sweep deep snows away. This has happened for thousands of years. Migrations, whether only a few or hundreds of miles, have been how game animals survive over time in a land that can be harsh and does not care about a cruel death.
Early on, biologists used radio collars and aerial surveys to get a handle on game migrations and populations, but much was still unknown about where and how the game moved across the land. Moreover, some of the studies and science could be siloed in an agency, not widely shared, and sometimes forgotten. In 2012, that began to change with the creation of the Wyoming Migration Initiative at the University of Wyoming. Key early figures included Bill Rudd, a now-retired former deputy chief of the wildlife division at the Wyoming Game and Fish Department, and Matt Kauffman, who holds a PhD. in environmental studies and heads the Wyoming Cooperative Fish and Wildlife Research Unit at UW.
Counters ready to take off on aerial elk census in February 1949. (WGFD file photo)
Today, with all the aforementioned technologies married to social and other forms of media, game migrations are front-of-mind in many places, with Wyoming the spear point. The invisible is now visible and accessible. A run-of-the-mill wildlife enthusiast can pull up a map from a website and see how a mule deer doe migrated from Steamboat Mountain just north of the Interstate 80 corridor outside Rock Springs, all the way north to her summer range within earshot of tourist traffic on Teton Pass in Idaho. That same person can see this amazing spectacle on game cameras and award-winning films, can visualize through technology the difficulties she faces from road crossings to river fords to predators — two-footed and four.
All of this has resulted in a contagious enthusiasm that has captivated state and federal leaders, as well as leadership at Game and Fish. In 2019, the department created a new position within the agency, and Jill Randall took over as big game migration coordinator as Governor Mark Gordon, an avid sportsman, issued an executive order emphasizing the importance of big game migration corridors in the state. Additionally, the federal government took interest in migrations and provided states with additional funding to monitor and map wildlife movements.
“I think there’s good reason to be encouraged right now,” Randall said. “Game and Fish has implemented monitoring, wildlife-friendly fencing, habitat projects and wildlife crossing projects around the state. There is a lot of public interest in migrations and there are all kinds of funding support, political support and public support for the agency to focus on conservation efforts on migration corridors and wildlife crossings.”
This support is the direct result of an impressive outreach effort by Game and Fish and WMI, which has revealed a depth of knowledge about big game migrations that previously was undocumented.
These mule deer in the Absaroka Mountains near Cody follow a trail during favorable weather conditions. (Photo by Tony Mong/WGFD)
Life on the move
Eight species of ungulates migrate in Wyoming, some only short distances and some across some of the most rugged terrain on the planet. The longer migrations are some of those of mule deer and pronghorn. Shorter are migrations of elk, bighorn sheep, mountain goats, white-tailed deer, moose and bison. But it is important to remember that the ability of wildlife to migrate is important whether those movements are short or more than 100 miles. There are mule deer that essentially stay put all year, too, while there can be bighorn sheep that travel many miles.
Mule Deer and pronghorn are not the only species that use wildlife underpasses. Moose, mountain lions and bears have been recorded using these structures with trail cameras. (Photo by Thomas Hart/WYDOT)
“They don't all have to look like Red Desert to Hoback,” Randall said. “That’s kind of the message we've tried to get out there. There are a whole variety of different ways migration and connectivity can look across the landscape.”
As the days shorten and cool in the fall, two factors can push animals out of high country basins — one human and one atmospheric. Big weather events like snow puts game on the move the most, but so does hunting pressure. As game moves onto winter range, the depth and duration of snow provides a consistent push. Since the quality of forage is better where there is more precipitation, animals will hang as long as they can in the high country. Sometimes they gamble and lose, Randall said, recalling a small group of pronghorn that got trapped by a significant snowfall early one fall. “That's one of those natural selection processes where it's like ‘well you didn't make a good choice, and so your genetics are not carrying on.’
Mule deer in the Absaroka Mountains near Cody sometimes have to migrate through tough winter conditions. Building enough fat reserves during the other seasons is important to surviving harsh winters in Wyoming. (Photo by Tony Mong/WGFD)
”There are far more hazards to migration than winter weather. The longer the migration, the more likelihood there are hazards. An animal coming down the mountain from the high country to a low-desert winter range might only have to contend with a few roads and fences. A longer route might take an animal across many highways, over or under many fences and even a possible swim through an icy river or two, not to mention subdivisions and other developments. Interstate 80 essentially stops all migration south and north. Animals coming from Baggs and other areas in southern Wyoming and migrating north are stopped by the interstate as are animals coming from the north and migrating south.
A trail camera captures pronghorn using an overpass to safely cross Wyoming Highway 191 west of Pinedale. Based on observations, pronghorn seem to prefer using overpasses instead of underpasses. (Photo by Thomas Hart/WYDOT)
In the spring, it is all reversed. As the snows melt, the animals head out, triggered mostly by what biologists call the green wave, an almost literal chasing of greening grass on the warming landscape. Pregnant does gain tremendous nutritional value from Sandberg bluegrass, also known as alkali bluegrass, which is the common early forage found throughout the sagebrush steppe.
Mule deer utilize an underpass under U.S. Highway 789 north of Baggs. (Photo by Chris Martin/WGFD).
Equally important are the stopover areas where herds pause in their migration and key in on greening slopes. In an area of abundant alkali bluegrass, animals might hold up for several days before making a big push to another area of abundant feed for another couple of rest days. Heavily pregnant does — pronghorn and mule deer — depend upon this burst of nutrition for healthy fawns. Feeding in the crepuscular hours, bedding, moving, feeding. Onward as their kind has for thousands of years.
So habitual are these movements that Randall and others have documented the young of known deer having their own fawns where they were born themselves.
Then there’s the case of mule deer doe 665, whose mother was 512, another research deer. Both wintered in the desert north of Superior in southwest Wyoming, but 512 summered in the Bondurant country where she gave birth to 665 in June 2021. The next year, 512 basically ghosted her daughter and made her way north. The daughter, also wearing a GPS collar, followed behind, retracing the migration route she’d been carried over in her mother’s belly the previous spring.
“She was two, then six, then 11 days behind her mother,” said Greg Nickerson, who runs WMI’s social media efforts and is currently working on a book about another remarkable deer, 255. “She followed along the same route into the Hoback Basin into the same summer range within two miles of her mom, and then she just kept going.”
Deer 665 crossed one of Wyoming’s busiest highways, U.S. 20/191 which sees about 10,000 vehicles a day. Then she swam the Snake River, skirted some subdivisions and a golf course, made her way up Teton Pass and popped into Idaho above Kelly Canyon where she summered. Then she returned to her winter range. The next year, she did it again, but for some reason, Idaho was not to her liking so she stayed on Teton Pass in Wyoming. She did it again in 2024 and again this spring, taking the month of May including stopover and travel days, to migrate back up to Teton Pass, 173 miles in all, before giving birth to twin fawns.
While it is the epic-long migrations that are the most remarkable, they all matter, said Nickerson. “There are all kinds of migration strategies, and they all matter. Some are short, some medium, some long. They all matter.”
— Tom Reed is the author of several books including, “Great Wyoming Bear Stories” and “Give Me Mountains For My Horses.” He lives with his family on a small dairy and horse ranch not far from an elk migration corridor.