CHEYENNE -- The U.S. Bureau of Land Management is telling its field offices to mark certain fences and guy wires to make them more visible to sage grouse, sharp-tailed grouse and lesser prairie chickens.
Studies have shown that barbed-wire fences can be deadly when these bird species fly into the fences without seeing them, although the number of birds killed depends on a variety of factors. Mortality tends to be a problem in places where large numbers of birds congregate frequently near fences.
Land managers and environmentalists are particularly concerned about the sage grouse, a hen-sized game bird that is being considered for protection under the Endangered Species Act. The U.S. Fish and Wildlife Service expects to decide early next year whether to list the sage grouse as endangered.
A directive from the BLM in Washington, D.C., earlier this month tells state BLM offices to evaluate fences for their risk to sage grouse and to place markers on the fences where appropriate. The directive also tells state offices to consider marking new fences as they're installed on BLM land.
In addition, the directive says guy wires for wind turbines and meteorological towers on BLM land should be marked.
A BLM official in Washington, D.C., wildlife biologist Geoffrey Walsh, said BLM offices in the 11 states where sage grouse exist already are taking many such steps. The directive basically tells BLM officials at the state and field-office level to keep doing what they're doing, Walsh said Wednesday.
"It becomes reassuring that what they've got going is supported," he said.
The environmental group Environmental Defense Fund praised the directive. U.S. Forest Service and BLM programs have resulted in 7,000 miles of new fence in the region over the past decade, said Ted Toombs, regional director for the Environmental Defense Fund's Center for Conservation Incentives.
"There's a lot of fencing being constructed and presumably little of it has markers on it," Toombs said.
Not every mile of fence is a problem. With sage grouse, fences seem to be more of a danger near breeding areas, where the birds congregate in relatively large numbers.
In Wyoming, which has vast expanses of sagebrush and relatively abundant sage grouse habitat, the BLM's Rock Springs Field Office has begun monitoring 33 miles of fence sections within 0.6 mile of breeding areas, said Chris Keefe, a BLM wildlife biologist in Cheyenne.
The first round of monitoring this year, Keefe said, showed evidence of as many as five birds per mile hitting fence. The fence sections were tagged with white vinyl markers and will be checked again next year.
"If we can reduce those mortalities, we would propose to expand that project substantially," Keefe said.
Sage grouse are found in Washington, Oregon, Idaho, Montana, North Dakota, California, Nevada, Utah, Colorado, South Dakota and Wyoming, as well as in Canada. Disappearance of sagebrush habitat is one reason why the birds are believed to have declined between 55 and 90 percent from their historic numbers.