The Trappers’ Point Antelope Trail – A Precarious Wildlife Corridor

By Emilene Ostlind

Pinedale— Trappers’ Point lies on an unassuming knoll along Highway 191, about six miles west of Pinedale proper.  According to a large wooden sign at the top of the hill, “Trappers, traders and Indians from throughout the west here met the trade wagons from the east to barter, trade for furs, gamble, drink, frolic, pray, and scheme.”  Between 1833 and 1840 this was the site of a half-dozen rendezvous.

Even before the trappers arrived, earlier people gathered here.  An archaeological site at Trappers’ Point revealed remains of 8000-year-old fire pits.  More recent layers in the site held 6000-year-old bones of pronghorn antelope that had been killed with stone-tipped tools. Today, cloaked in windblown shrubs and dusty rocks, necklaced by barbed wire fences and power lines, this knoll hardly seems a prime destination.  But people were not drawn here by the view of the gravelly hilltop.

In contrast to the surrounding high-elevation sagebrush desert and rocky alpine peaks of the Wind River Mountains, this is a place rich in water, forage, and wildlife.  The bottomland of the New Fork River sweeps within a half-mile of Trappers’ Point to the northeast, and that of the Green River within a half-mile to the west. The arcs of the two rivers form a natural geographic bottleneck here.  Viewed from above, Trappers’ Point is the middle of a narrow bridge of land linking the entire Green River Basin to the south with the Upper Green River Valley and surrounding mountains to the north.

Trappers’ Point has attracted human visitors for thousands of years because it is the center of one of the world’s largest intact long-distance animal migrations.

Tucked between high rugged mountains on its north end and sprawling southward toward Utah and Colorado, the Green River Basin stretches across more than 4000 square miles of southwestern Wyoming.  The basin is a desert where, for most of the winter, grass and shrubs poke through the thin, windblown snow.  The abundance of hardy forage and the sparse snowpack make this an important winter range for as many as 100,000 ungulates, including about 59,000 antelope, the largest gathering of pronghorn on Earth.

Through April and May, although some antelope remain in the basin year round, tens of thousands disperse from the Green River Basin to summer ranges across western Wyoming, moving into the foothills of the Wyoming, Gros Ventre, and Wind River Mountain Ranges. At least 3500 of these antelope pass through Trappers’ Point each spring to reach their summer ranges around Hoback Canyon and along the Upper Green River.

One group of about 400 antelope migrates all the way to the grassy benchlands of Grand Teton National Park.  At 170 miles one way, the journey of the Teton pronghorn antelope is the second longest recorded land animal migration in the Western Hemisphere, after caribou in the Arctic.  The members of the Teton antelope herd cross a 9000-foot pass in the Gros Ventre Mountains and swim through four major rivers– the New Fork, the Green, the Gros Ventre, and the Snake–to reach their summer range in the Park.

Around the world, long-distance animal migrations are disappearing due to loss of habitat, development blocking off corridors, or people killing the animals.  In the Greater Yellowstone Ecosystem (which is connected to Trappers’ Point through the movement of the pronghorn), six of eight historic big-game migration corridors have been blocked and are no longer available to the animals that once relied on them.  When that happens, the deer, elk, bison, and antelope are restricted to isolated ranges where they are susceptible to harsh weather, inbreeding, or disease.

In the case of the Teton herd, obstruction of the corridor would mean that antelope could no longer reach Teton Park, where every summer millions of visitors from around the world see them as they raise their fawns.  Every adult antelope in Teton Park has crossed the Trappers’ Point bottleneck to get there.

For a patient visitor, a good springtime perch from which to watch Trappers’ Point is on the north side of Highway 191, where dirt two-track roads lead onto the federal Bureau of Land Management land on Cora Butte.  Bring a spotting scope, a chair or mat to sit on, and a warm coat, and be prepared to wait for several hours– or even days.

If your timing is right, you may see a cluster of migrating antelope appear over the rim of the Mesa and make their way with determination into the bottleneck.  The group approaches the highway where the taut strands of a barbed-wire fence stop them.  Ears tilted forward, the leaders watch semis, cars, and pickups zip back and forth along the highway.  They follow the fence downhill toward the opening of an underpass in a sort of gully.

The antelope peer into the dark tunnel under the highway.  In a 2008 pilot project in Nugget Canyon west of Kemmerer, the Wyoming Department of Transportation installed six wildlife underpasses.  The tunnels were equipped with motion-sensor cameras, which have documented thousands of mule deer, as well as a handful of moose and even a few antelope, trotting through.  Highway collisions between vehicles and wildlife have declined significantly since the installation of those passages.

However, of all of the many times I’ve watched antelope approach the underpass at Trappers’ Point, I’ve never seen one enter it.  Antelope rely on their keen eyesight and their ability to escape danger by sprinting away at up to 60 miles per hour.  Venturing into a narrow underground passageway is simply too risky for them.

Instead, the antelope follow the fence line away from the underpass, up to the level of the highway.  They may run back and forth along the fence for 45 minutes or longer, watching traffic and searching for a way through.  Finally, one of the antelope selects a space between fence posts, where the bottom wire is very slightly higher above the ground than anywhere else.  She drops to her knees (actually, her wrists), ducks her head, and shimmies through.  The others watch her and then follow, one at a time, scooting under the fence.

The agitated animals gather in a knot on the asphalt.  Drivers speeding up from Pinedale or Daniel usually see the animals in time to stop, but sometimes bodies of dead antelope lie on the shoulder of the highway.

Managers have long known that Trappers’ Point is a critical wildlife crossing.  An elaborate system of motion sensors and signs borders the highway.  When the motion sensors detect an animal passing between them, they trigger flashing lights on the signs, which read “deer on roadway.”  However, the motion sensors don’t always detect animals, or they misfire and the signs flash when no animals are present.  Drivers may become habituated to the false signal and ignore it altogether.

Once all the antelope are through the fence and across the highway, they encounter a second fence.  Again, the lead antelope searches the barrier until she finds a space to slip under the bottom wire.  Antelope have thin, stilt-like legs built for running rather than leaping.  I’ve only rarely seen a buck antelope jump a low fence, and I’ve never seen a doe or fawn do it.  Sometimes when an antelope attempts to jump a fence its rear foot may be caught between the wires in a twist and it can die hanging in this wrenched position.  If antelope reach an impenetrable fence during migration, especially a woven-wire sheep fence, they can be trapped and starve or freeze to death in deep snow.

Luckily, the thousands of antelope that cross Trappers’ Point are still able to navigate this important section of their migration corridor.  Thanks to a special designation in 2008 by the federal Bureau of Land Management, about 9500 acres were set aside as an Area of Critical Environmental Concern.  This designation protects the bottleneck from natural gas mining and off-highway vehicle use.

Furthermore, the Green River Valley Land Trust, a local conservation group, has worked to retrofit many miles of fence so that antelope are able to crawl underneath.  A wildlife-friendly fence has a barbless bottom wire that is at least 16 inches above the ground.

Trappers’ Point presents another opportunity for protecting this wildlife migration.  Wildlife overpasses have seen great success in Banff National Park in Alberta, and are being built in other areas as well.  These structures span the highway like giant bridges and are surfaced with grasses and native vegetation.  To antelope and other wild animals, the overpass looks like a hill.  Traffic on the roadway drives underneath through a tunnel.

The National Fish and Wildlife Foundation estimates the cost of building a Trappers’ Point overpass would be about $5 million.  The Wyoming Department of Transportation applied for $100 million in federal economic recovery money to build many wildlife overpasses and underpasses on Wyoming highways, where an average of about 1,800 collisions between vehicles and wildlife are reported annually.  That application for funding was denied in early 2010.

However, momentum is building for wildlife corridor protection across the nation.  In 2008 the Western Governors’ Association created a Wildlife Council charged with creating a database of information the states can reference to prioritize corridor protection areas.

On Earth Day in 2010, U.S. Representative Rush Holt from New Jersey introduced the Wildlife Corridors Conservation Act which, if passed, will gather information about wildlife corridors and create a Wildlife Corridors Stewardship and Protection Fund.  Furthermore, the Wyoming Department of Transportation will apply later this summer for a second round of economic recovery funding, which is prioritized for rural highway projects.

Pat Collins, the State Engineer for Engineering and Planning at the Wyoming Department of Transportation is optimistic that this second application will bring in the necessary funds.

“We should find out, I’m not sure, but I think in mid September,” he says.  “If the money comes through we expect to begin construction on the overpass next spring.”

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Emilene Ostlind is a graduate student at the University of Wyoming, finishing her degree in creative nonfiction writing and environment and natural resources.  Her thesis project is a book documenting the migration of pronghorn antelope from Grand Teton National Park to their winter range in the Green River Basin.  Emilene grew up in Big Horn.

Joe Riis is a wildlife photojournalist focusing on conservation and wildlife corridors. Joe is 25, a National Geographic Young Explorer, and the Freedom To Roam staff photographer. Joe grew up on the Great Plains in South Dakota and graduated from the University of Wyoming in Wildlife Biology.