With the return of spring, a band of pronghorn begins moving north from their winter range in the Upper Green River Valley of Wyoming. As they travel, they are joined by others and together they follow the retreating snow north as it uncovers new, green growth. Journeying along the Green River, they pass through the ‘Funnel’ — a narrow water gap cut by the Green River — towards the hydrologic divide between the Green River of the Colorado River system and the Gros Ventre River of the Snake River system. Crossing the divide, the band, now numbering several hundred, travels down the Gros Ventre valley towards their goal — their summer range in Jackson Hole and Grand Teton National Park; overall a migration of more than 100 miles. In Jackson Hole, the does give birth, typically to twins, and spend the summer raising their fawns. With the approach of fall, the pronghorn begin to gather; anticipating their return trek back to their Upper Green River Valley winter range — for they cannot survive the deep snows of a Jackson Hole winter. There is greater urgency and purpose during their return journey — they must cross the Gros Ventre/Green divide before snow blocks their way. And during their return journey, a new generation learns the Path of the Pronghorn.
Since 2003, WCS scientists have been studying the Path of the Pronghorn. Using field research and GIS analysis, WCS has documented that housing developments, roads, and fences are threatening to sever the corridor at several crucial bottlenecks. WCS has led the effort to secure formal recognition and permanent protection for this fragile migration route.
The Path of the Pronghorn is one of the longest large mammal migration corridors remaining in North America. If this migration corridor is lost, one of the western U.S.’ iconic species will vanish from one of our most scenic national parks.
Archeological evidence suggests that this annual migration has been repeated for almost 6,000 years. Currently, the migration, and hence the viability, of pronghorn in Grand Teton National Park is jeopardized by large-scale energy development, increasing private land development, and imbalanced predator/prey relationships.
Through a coordinated program of field-based research to identify and assess threats to the Path of the Pronghorn, outreach to build support for its protection, and cooperative actions to make its protection a reality, the Wildlife Conservation Society is working to ensure that pronghorn will be able to make this awe-inspiring migration for another 6,000 years.
The goal of this study is to develop and implement a strategy to conserve the Path of the Pronghorn the longest remaining migration corridor in Greater Yellowstone, ensure the local survival of pronghorn antelope, and set a precedent for similar efforts elsewhere.
WCS biologists are studying the biological costs of disturbance from increased energy development on pronghorn wintering grounds, and obtaining fine-scale information about the different pathways utilized by these animals to move from summer grounds in Grand Teton National Park to wintering grounds in the Red Desert region south of Pinedale, Wyoming. The retention of a migratory species in an accessible national park and the sensational nature of long-distance travel represent a phenomenon of immeasurable conservation value.
WCS’s work along the Path of the Pronghorn also involves:
- Placing radio-tracking collars on individual pronghorn to obtain fine-scale information on pronghorn migration travel routes and patterns.
- Documenting survival rates of pronghorn antelope fawns, including impacts of predators and winter survival.
- Collaborating with stakeholders to ensure that critical passes and constricted sections of the migration route remain open.
- Conducting behavioral studies to assess the energetic cost of increased disturbance on pronghorn antelope from expanding human activity as related to energy development.
- Evaluating the impacts of human activities on this migration and to use research results to help inform local management.
- Providing information to resource management agencies, key private landowners, and local conservation organizations to facilitate stronger cooperation to protect this pronghorn population and remnant migratory pathway.
In 2008, the U.S. Forest Service established the nation’s first federally designated wildlife corridor. First recognized through research conducted by Drs. Joel and Kim Berger of WCS and Grand Teton National Park biologist Steve Cain, the Path of the Pronghorn, corridor between Grand Teton National Park and the Wyoming’s Upper Green River Valley, is one of the longest remaining terrestrial mammal migration corridors in North America, and the longest left in the Greater Yellowstone Ecosystem.
From the start, WCS led efforts to change public and private land management to protect this extraordinary migration. The decision by the Forest Service to incorporate federal protection for the 45-mile long portion on national forest land comes after leaders from three federal agencies formally pledged their support for permanent path protection in January 2008 and after the Western Governors’ Association pledged to support wildlife migration corridors and crucial habitat in the 18 western states. WCS’s Corridor Conservation Initiative works with NGO and agency partners to secure protection for wildlife corridors, such as the Path of the Pronghorn, throughout the western United States.