Sagebrush sparrow declines linked to Wyo. drilling fields
Reprinted with permission from Environment & Energy Publishing, LLC. Not for republication by Wyoming media.

A new study suggests that intense oil and natural gas drilling on federal land is wiping out sensitive species of sparrows in southwest Wyoming, prompting environmental advocates to demand the Bureau of Land Management rein in high-density drilling projects.

The study, conducted by researchers at the University of Wyoming and published recently in the peer-reviewed Journal of Wildlife Management, concludes that populations of Brewer’s sparrows, sage sparrows and vesper sparrows drop as the number of oil and gas drilling well pads per square mile increases.

The study analyzed sparrow populations in the Upper Green River Basin’s booming Pinedale Anticline and Jonah Infill natural gas fields, as well as the Big Piney-LaBarge oil field. Researchers concluded that “increased well density was associated with significant decreases in Brewer’s sparrow and sage sparrow abundance, particularly in the Jonah natural gas field.”

The study suggests that limiting the number of well pads per square mile could help offset these declines, and that failure to do so “will further exacerbate regional declines of sagebrush songbirds,” according to the eight-page study.

Anna Chalfoun, a study co-author and research scientist at the University of Wyoming’s Cooperative Fish and Wildlife Research Unit, said in a statement that the results hint at a direct correlation between the number of wells per square mile and sparrow counts.

Chalfoun also noted that while much research has focused on drilling’s impacts to greater sage grouse and big-game species like mule deer and Rocky Mountain elk, very little attention has been paid to drilling’s impacts on smaller species that also depend on the region’s dwindling sagebrush steppe habitat for survival.

While conceding that oil and gas drilling activity is not the sole factor influencing songbird population declines, Chalfoun said researchers are still investigating whether increased human activity, including at drill sites, has attracted sparrow predators such as ravens.

Nevertheless, the study comes as federal regulators are reviewing proposals to dramatically expand natural gas drilling activity in the region, including a proposal by Calgary, Alberta-based Encana Oil & Gas USA to drill as many as 3,500 gas wells on nearly 141,000 acres of land managed by BLM in Sublette County.

If approved, the Encana proposal, called the “Normally Pressurized Lance” project, would be among the nation’s largest natural gas fields, producing trillions of cubic feet of gas over 50 years and essentially quadrupling the size of the Jonah Infill and more than doubling the 1,200 wells in place there today (Land Letter, May 12).

Nothing ‘new or surprising’

Dennis Saville, a BLM wildlife biologist in Cheyenne, Wyo., downplayed the study’s findings, noting that the research does not “present any new or surprising information” and fails to address broader issues facing sparrow populations.

“We know that active energy development areas are not going to be attractive areas for nesting migratory birds and some level of avoidance would be expected,” Saville said in an emailed response to questions.

“However,” he added, “the study does not explain regional declines for these species. There are literally millions of acres [of] non-impacted sagebrush habitats still present in Wyoming, but the declines in these birds has occurred across the entire region.”

Saville defended BLM’s management of the large drilling projects in the Upper Green River Basin, noting that the agency requires directional drilling in many areas of the Pinedale Anticline area as well as places seasonal restrictions on drilling activity to protect a number of sensitive species.

Saville also said that part of BLM’s National Greater Sage Grouse Planning Strategy unveiled in July includes amending more than 70 resource management plans across the bird’s 11-state range to include strategies designed to protect the grouse and also its dwindling sagebrush steppe habitat.

That, in turn, “will also conserve sagebrush habitats for many other species including these sagebrush dependent migratory birds included in this study,” Saville said.

Need for action?

But some environmentalists say the study’s conclusions are troubling and warrant immediate action.

Erik Molvar, a wildlife biologist with the Biological Conservation Alliance in Laramie, Wyo., said BLM has unnecessarily allowed intense drilling activity in sparrow habitat even as it identifies the birds as “sensitive species” that must be taken into account when permitting new projects.

Molvar said BLM has permitted projects that allow as many as 64 well pads per square mile in the Jonah Infill, where the latest study suggests that Brewer’s sparrow and sage sparrow populations have been hit hardest.

“This study underscores the need for the BLM to require directional drilling to reduce the footprint of oil and gas development so that dozens of wells are drilled directionally from each well pad and well-site densities are less than one pad per square mile,” he said.

With advances in directional drilling technology, “There’s really no excuse for having a well density of more than one well pad per square mile,” Molvar added.

But Cheryl Sorenson, vice president of the Petroleum Association of Wyoming, said directional drilling is not a viable option at all drilling sites that contain sparrow habitat. “Directional drilling is not always feasible in all areas, not only economically, but practically,” she said.

She added that oil and natural gas drilling operators are conscientious about environmental issues, including “sensitive species that need to be protected in the state of Wyoming.”

Click here to read the study.

Streater writes from Colorado Springs, Colo.

(Banner photo taken by Bill Bouton)

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