Wildlife advocates are due in federal court Tuesday seeking an injunction to stop gray wolf hunts already well under way in the Northern Rockies.
Federal biologists say the wolf population is healthy enough to support the hunts in Idaho and Montana. The two states want to drive down the predators' numbers to curb their attacks on livestock and big game herds.
But wildlife advocates say too many wolves are being shot too quickly, threatening to unravel the species' decades-long recovery and killing animals closely followed by wolf watchers.
More than 150 wolves have been shot since hunting began in late August.
Tuesday's hearing is before a three-judge panel of the 9th U.S. Circuit Court of Appeals in Pasadena, Calif. The hunts were allowed after Congress last spring took the unprecedented step of stripping endangered species protections from more than 1,300 wolves. That prompted a lawsuit from wildlife advocates who say Congress overstepped its bounds by effectively reversing prior court rulings that favored protections for the animals.
The 9th Circuit has agreed to hear the case on an expedited basis. But several groups involved in the lawsuit requested an injunction to stop the killing of wolves while the case is pending.
"We perceive a continuing threat not just to the population in total but to particular individual wolves. Even if the court is going to delay another three months, we would like them to stop the hunt while they consider the case," said attorney Jay Tutchton with plaintiff WildEarth Guardians.
Two previous injunction requests were denied.
Tuesday's hearing marks the latest in two decades of courtroom battles over wolves. Prior lawsuits resulted first in the animals' reintroduction to the region and then later kept them on the endangered list for a decade after the species had reached the government's original recovery goal.
The U.S. Fish and Wildlife Service is monitoring the hunts, but agency officials said they have no plans to intervene because wolves have recovered in the region and the states have promised to manage them responsibly.
Montana's quota was set with the goal of reducing wolf numbers by 25 percent compared with last year, to 425 animals.
Idaho officials have said only that they plan to maintain at least 150 wolves, out of a current population of at least 700 animals.
So far this year, wolves in Montana and Idaho have killed 152 cattle and calves, 108 sheep, 12 dogs and three horses, according to confirmed kill tallies provided by state and federal officials.
Even without hunting, wolves are shot regularly in the region in response to livestock attacks. At least 103 of the predators had been killed this year by government wildlife agents and ranchers.
If wolf numbers drop below 100 animals in either state, federal officials would step in to restore endangered species protections. That safety valve undercuts the plaintiffs' contention that the hunts could cause irreparable harm, attorneys for the government contended in court documents filed in advance of the hearing.
The attorneys wrote that an injunction would be an extraordinary step for the court to take and that the plaintiffs "come nowhere close to meeting the test."
They also argued that Congress was within its bounds to act on the issue, because lawmakers had been informed by government scientists that wolves were biologically recovered.
"Congress had the right to make that policy choice," Assistant Attorney General Ignacia Moreno wrote. He added that the plaintiffs' separation of powers argument was flawed. Moreno also cited prior court opinions that called for a "high degree of judicial tolerance" when Congress intervenes in a matter subject to litigation.
Sporting and gun rights groups including the National Rifle Association and Safari Club International have intervened in the case on the side of the federal government.
Wyoming Gov. Matt Mead recently struck a deal with Interior Secretary Ken Salazar that could allow wolf hunting in that state as early as next year.
First the plan has to be approved by Wyoming lawmakers. A legislative committee was scheduled to discuss the issue Tuesday, although final action would not come until early next year.
Congress left Wyoming out of a budget bill rider in the spring that took wolves off the endangered list across five other states. Federal wildlife officials said at the time that Wyoming's wolf law was too tough on the animals to ensure their long-term survival.