At a site called Trapper's Point about six miles west of Pinedale, Wyo., the New Fork and Green rivers sweep toward one another and then away, creating an hourglass shaped strip of land. Every spring and fall more than 3,000 pronghorn and mule deer pass through this bottleneck as they travel between winter range in the Green River Basin and summer ranges in the surrounding valleys and foothills. This includes members of the Teton pronghorn herd, who undertake the longest known land animal migration in the continental U.S. when they move 170 miles to summer in Grand Teton National Park.
A housing development blocks off part of the already narrow corridor at Trapper's Point, restricting the pronghorn to a passage just a half mile wide. Right in the middle of this pinch point, the migrating animals must cross Highway 191, the road linking Pinedale to Jackson. Vehicles kill around 100 big game animals on this highway every year. Often, the still lump of a pronghorn carcass lies on the shoulder of the highway.
In this gauntlet of fences, highways and
Vehicle collisions with wildlife decreased significantly on two other Wyoming highways after WYDOT built systems of wildlife underpasses. Cameras installed in underpasses below Highway 89 in southwest Wyoming during 2008 show thousands of deer plus other species like moose and elk walking through. But antelope rely on eyesight to keep them from danger, so they tend to avoid dark, narrow underpasses like an existing concrete opening under the highway at Trapper's Point. Here, migrating antelope follow the fence line to the underpass and peer into its shadowy opening. Thanks to newly-allocated funding, Wyoming will have its first overpasses to help pronghorn. Preventing collisions will save enough money to pay for the overpass in less than 20 years, while protecting wildlife and drivers.
More importantly, the structures blur the distinction between places set aside for wildlife versus those set aside for humans. By reconnecting fragmented habitat, we invite more robust wildlife populations to share the places we live and work in the West.
Emilene Ostlind holds an editorial fellowship at HCN.
Photo of buck pronghorn crossing highway in Teton Park courtesy of Flickr user alh1.