Even by Wyoming standards, the scene of a Jan. 15 wildlife-vehicle collision in a Sublette County gas field was shocking.
Game warden Brian Nesvik responded to a report of a wildlife accident to find 21 dead or dying pronghorn strewn along an unfenced service road in the Jonah gas field outside Pinedale.
Nesvik has concluded the collision occurred when a herd of pronghorn inexplicably stampeded into a truck, leaving a scene of carnage possibly unprecedented in the history of western highways. A Pinedale-based investigator for the Wyoming Department of Game and Fish, Nesvik said he could find no clues to explain why the pronghorn dashed onto the road.
Because there is no evidence of wrongdoing or irresponsible driving, wildlife and sheriff’s officials believe the collision was a freak accident and expect to file no charges. The collision occurred in broad daylight and the woman driving the one-ton pickup, a gas-field water hauler, was traveling the road’s 35 mph speed limit.
The intersection between big game and vehicular traffic has yielded countless wildlife deaths on Western highways, especially in Wyoming, a state blessed with vast herds of free-roaming big game. The state is home to some 500,000 pronghorn, North America’s fleetest land mammal and the signature species of big game on the high prairies of the Rockies. Still, the Sublette accident appears to be a mind-boggling fluke. How could one vehicle kill so many animals? Nesvik, who has investigated his share of road kills, could only guess.
He speculated the pronghorn were running along the right side of road in the same direction as the truck when they suddenly veered left. With the animals coming from her blindside, the driver had no time to react.
“I’ve seen pronghorn do that, run together in a group and turn really quickly,” Nesvik said. “In this situation, it would have been better if the driver had been going faster.” The investigator looked into other mass-casualty wildlife collisions and found none that involved more than eight fatalities. (Editor’s Note: Other deadly roadkill incidents have come to light since the original publishing of this article. See Brian Maffly’s followup on this story here.)
The pickup’s driver, the only occupant, was uninjured in the incident, but her truck sustained serious body damage. The vehicle, however, had left the scene by the time Nesvik arrived in response to the call.
The body count included 13 does, four bucks and four fawns. Nesvik and a passerby used firearms to kill a few pronghorn that survived the impact. Seven or eight had injuries consistent with having been run over, Nesvik said. The others appeared to have run into the side of the truck.
The accident renews attention on the impact of extensive natural gas development occurring in important winter wildlife habitat administered by the Bureau of Land Management in Wyoming’s Upper Green River Valley. Thousands of mule deer and pronghorn congregate on the wind-blown sage-covered mesas near Pinedale where they find pockets of forage in the high-desert valley between the Wind River and Wyoming ranges.
Industry-backed research has documented an exodus of mule deer from the Upper Green’s crucial winter range near wells and roads. Despite these findings, the BLM is proposing to waive seasonal drilling restrictions on the Pinedale Anticline, a gas field next to the Jonah, and to allow a major increase in development. The agency has already approved a massive “infill” drilling project on the Jonah that will add another 3,100 wells. The mass road kill incident indicates gas-field traffic may be a greater threat to big game than anyone anticipated.
“The fact that this woman seems to have been driving responsibly makes this incident even more significant,” said industry critic John Amos, who heads SkyTruth, an organization that documents environmental impacts over time using satellite imagery. “The BLM needs to require BMPs [best management practices] to minimize roads and traffic in these fields, because current operations are obviously not protecting wildlife.”
(Full disclosure: the author Brian Maffly is a staff member of The Wilderness Society, a national conservation organization working in Wyoming to minimize the impacts of Upper Green gas development on wildlife and other natural values. Brian can be reached at firstname.lastname@example.org.)