"He had been pretty effective early on, but it had been two weeks since he had taken any wolves, so we decided there was no reason to keep him in the area any longer," Keckler said.
Keckler said the average size of a wolf pack in Idaho is five wolves, so the agency determined it had reached its goal of eliminating the Golden Creek and Monumental Creek packs. Officials announced Monday that Thoreson was coming out.
Fish and Game Director Virgil Moore's acknowledgement that Thoreson's hunt relied on the use of the U.S. Forest Service's backcountry airstrips and cabin had prompted strong emotions, including from wolf advocates who sued in federal court to force him to quit.
Defenders of Wildlife, Western Watersheds Project and Wilderness Watch filed the lawsuit Jan. 6 asking the judge to stop the plan immediately to give the case time to work through the courts. The environmental groups were joined by Ralph Maughan, a former Idaho State University professor, conservationist and long-time wolf recovery advocate from Pocatello.
They lost their initial bid on Jan. 17 when a federal judge rejected their request for a temporary restraining order. The conservation groups argued that Thoreson's activities violated the 1964 Wilderness Act and other federal acts.
The groups had appealed that decision to the 9th U.S. Circuit Court of Appeals.
Tim Preso, an attorney for Earthjustice representing the groups, said Wednesday that the Idaho Department of Fish and Game faced a Tuesday deadline to file a legal brief concerning the appeal, but pulling the hunter made that unnecessary.
"Instead they were able to sidestep all that," he said, adding the groups are considering their next move.
"I am happy that the Idaho Department of Fish and Game has relented, but it is unfortunate that so many wolves have been taken in this senseless plan to manhandle wildlife in an area that Congress recognized as a wilderness," said Ken Cole, National Environmental Policy Act coordinator at the Boise office of Western Watersheds Project.
Wolves were reintroduced to Idaho in the mid-1990s and have since flourished in backcountry regions, including the Frank Church wilderness.
Last year, state game managers estimated Idaho's wolf population at 683, an 11 percent drop from 2012. The highest total was in 2009, when it estimated 859 wolves were in the state.