Kim berger and I climb a ridge on horseback to get a view of a key pass that the pronghorns must cross. Here, south of Grand Teton National Park, the corridor rises into mixed conifer forest. The view is stunning: we see the upper reaches of the Gros Ventre River, which flows northward into the park, and high meadows where pronghorns meander. Kim points out the "Red Hills bottleneck" in the distance, one of many natural constrictions that migrating animals face. On a steep slope above rapids and below an impassable cliff band, antelope hoofs have carved a single-track trail. "These animals literally come over the same hoofprints year after year," Kim says, adding that they cover the 120-mile passage between their summer and winter ranges in about three days at a brisk, nose-to-tail walk.
We skirt the edge of the woods, peering down the treeless flood plain where pronghorns graze in scattered small gatherings. They don't migrate in huge herds, Kim tells me, but in groups of three up to a dozen. But migrate they must: deep snows in the higher elevations would kill them if they stayed the winter. In 1993, wildlife managers documented a group of stragglers that got trapped by an early snowfall and died.
On the other side of the ridge, the pronghorns have to negotiate a difficult stretch west of the Green River. The route between the river and some aspen groves has grown narrower and full of obstacles with the recent proliferation of ranchette subdivisions, with their attendant fences and guard dogs. Pronghorns, Kim explains, don't like to go places where they can't "see far and run fast." If the animals reach Highway 191, which runs through Pinedale, they must pass through one last natural bottleneck, Trapper's Point, a quarter-mile-wide passage that has been a gantlet of sorts for millennia. During construction to improve Highway 191 in the early 1990s, archaeologists discovered the bones of butchered pronghorns dating back 6,000 years, including fetal bones. Native Americans had hunted the animals at this bottleneck during the spring migration, when females were pregnant. Today in this spot, it's cars that are lethal.
Sublette County, where these pronghorns live from about November through April, is the fastest-growing county in Wyoming. An increasing number of wealthy second homeowners are quickly subdividing—and fencing—previously wide open spaces. Some landowners have worked with wildlife officials to make pronghorn-friendly fences that provide access points for the antelope. But others have put up virtually impenetrable barriers. The cumulative effect of all this construction, Kim Berger says, could be devastating to the pronghorn herd: "It takes only a small difference to switch the balance from a stable population to one that's declining."
At best, the arid Pinedale Mesa is a land of "just enough": just enough protein in sparse sage leaves to sustain pronghorn; just enough water that deer can paw from frozen seeps and suckle from snow; just enough shelter from icy winds amid the hillocks. About 100,000 deer, moose, elk and pronghorns (from Grand Teton and elsewhere) winter here.
The animals' resources have been shrinking ever since people figured out how to eke out a living here. Revenue from oil and gas production provides the base for Wyoming's economy, keeping taxes low and allowing the state to run a budget surplus. Beginning in the late 1990s, breakthroughs in hydraulic fracturing (known as "fracing," pronounced "fracking"), which pumps liquids at high pressure deep into the earth to break up sandstone blocking access to valuable methane gas pockets, have altered the landscape. There is at least 20 trillion cubic feet of methane gas near Pinedale, most of it on federal land—about one year's supply of natural gas for the country. The more drilling became profitable, the more Pinedale boomed: bulldozers carved miles of dirt roads through the sage flats, and drilling pads multiplied almost as fast as the gas companies could hire construction workers to build them.
The Pinedale area quickly became the focal point of a debate. To people like Charles Stanley, executive vice president of the Questar Corporation, the area provides a rare, concentrated accumulation of an important energy resource—a place where Questar and other energy companies could demonstrate new techniques that they say minimize drilling's impact on land and wildlife. For instance, they drill in multiple directions from one "fixed pad" to reduce land disturbance. "I believe we can and have as an industry achieved an acceptable balance that protects the environment while still accomplishing development of the nation's third-largest natural gas accumulation," says Stanley.
But for many local residents, the influx of energy developers has not been so salutary. Bouncing along dirt roads south of Pinedale, Linda Baker guides her Saab around vast sage steppes punctuated by drilling rigs and evaporation ponds. "Seven years ago this was a place where there was very little development," says Baker. Now the area has been carved into a pocked, checkered industrial zone that looks more like Texas' oil fields than Wyoming's vast vistas. "It's heartbreaking," she says.
Baker, who has lived in Pinedale for 25 years, is herself a former "juggie," a geophysical explorer for oil and gas companies. After a stint in the fields, she used her earnings to return to school, and she eventually became a librarian—until the recent gas boom propelled her into full-time advocacy. Baker helped form the Upper Green River Valley Coalition in 2002. The coalition won a temporary halt to oil and gas leasing in a nearby national forest and a withdrawal of leases near the Trapper's Point bottleneck. "We have been able to help define a vision for our future as oil and gas development rushes around us," Baker says.
Baker's soft voice belies her passion for her hometown. She points out that the fluids used in fracing can contain solvents such as benzene, toluene and xylene. These compounds are highly carcinogenic, and Baker fears they will contaminate the drinking water supply.