By MATEUSZ PERKOWSKI

Capital Press

Ranchers in Arizona have failed to convince a federal appeals court that the U.S. government overstepped its authority in designating critical habitat for the threatened Mexican spotted owl.

On June 4, the 9th U.S. Circuit Court of Appeals found that the U.S. Fish and Wildlife Service had properly designated 8.6 million acres in Arizona, New Mexico, Colorado and Utah as critical habitat for the species.

Under the Endangered Species Act, the Fish and Wildlife Service must delineate areas of "critical habitat" required for the survival and recovery of listed species.

Such designations are generally associated with increased restrictions and scrutiny of grazing and other activities on federal land.

The history of critical habitat designations for the Mexican spotted owl is particularly contentious.

Since the mid-1990s, lawsuits have repeatedly prompted the Fish and Wildlife Service to establish and then revoke such designations, with the size of the critical habitat ranging from 4.6 million to 13.5 million acres.

The agency's most recent designation was finalized in 2004 and challenged by the Arizona Cattle Growers' Association two years later.

The group, which represents about 850 ranching operations, claimed the designation's boundaries weren't legally justified and would reduce the amount of grazing on federal lands.

A federal judge rejected the association's arguments and that decision has now been unanimously affirmed by a three-judge federal appellate panel.

The court's opinion largely centered on how the Fish and Wildlife Service determines whether land is "occupied" by the owl.

Ranchers claimed the agency impermissibly included areas where no owls actually resided.

The definition of "occupied" is tough to nail down for a bird that migrates and uses different areas with varying frequency, according to the ruling.

However, the appellate court said it must defer to the agency's expertise in regard to such specific and fact-dependent questions.

"The FWS has authority to designate as 'occupied' areas that the owl uses with sufficient regularity that it is likely to be present during any reasonable span of time," the court said. "This interpretation is sensible when considered in light of the many factors that may be relevant to the factual determination of occupancy." The ranchers also claimed the economic burden of the designation wasn't given proper weight.

The agency's analysis reflected a relatively light economic burden because Endangered Species Act restrictions would exist regardless of the critical habitat designation.

The appellate court ruled the agency correctly considered the previously imposed burden in its economic analysis.