The pronghorn that summer in and around Grand Teton National Park conduct one of the longest terrestrial migrations in the lower 48 states. As snows begin to fall each autumn, some 300 to 500 animals depart the high valleys of the Park for the Green River Valley, approximately 125 miles southwest. On their migration to the Green River Basin of Wyoming, the pronghorn must pass through housing subdivisions, negotiate fences, and cross a busy highway. Adding to the stress of the migration itself (which the females do while quite pregnant – with twins – each spring), the wintering grounds have been rapidly developed as natural gas fields.
Once the pronghorn arrive at their wintering grounds, they find sagebrush in the valley that provides some of the highest quality wildlife habitat in the West. In addition to the pronghorn, the area supports the largest sage grouse population in the state, the second largest herd of mule deer, and populations of elk. Wintering grounds in the Valley for the various ungulates are crucial, because available winter forage is the factor that often limits their survival.
NFWF's Path of the Pronghorn Conservation Program helps pronghorn and other animals migrate more easily by improving fencing and removing other impediments to their passage. It focuses on efforts to reduce the effects of roads on wildlife, and protect key parcels where subdivision and development imperil the entire migration corridor.
Through this program, NFWF and partners have helped protect more than 40,000 acres of land in the migration corridor and retrofitted or removed 120 miles of problem fencing, enabling pronghorn to pass. In the fall of 2012, pronghorn successfully migrated through Trappers Point, WY using a recently-constructed highway overpass. Additional highway overpasses and underpasses are being built by the Wyoming Department of Transportation in order to facilitate safe crossing of pronghorn during migration. The first of their kind in pronghorn country, these structures are expected to reduce mortality in the herd and, with support from NFWF, scientists from the Wildlife Conservation Society are studying the pronghorn response to the structures. Lessons learned here will be applied to other road crossing structures under consideration in pronghorn country.
For more detail on priority activities, please see NFWF’s Business plan.