Idaho Fish and Game commissioners decided Monday to open about one-fifth of their state's wolf population to public hunting.

Wolf advocates responded with promises of legal action demanding the predator's return to endangered species protection.

Meeting Monday afternoon in Idaho Falls, the Idaho Fish and Game Commission set a quota of 220 wolves for that state's 2009 hunting season.

The season runs from Sept. 1 to March 31 in two hunting zones near the Montana-Idaho border, and from Sept. 15 to Dec. 31 in two other zones. The remaining eight hunting zones have a season of Oct. 1-Dec. 31.

( Permits for the Montana wolf-hunting season, which starts Sept. 15, go on sale Aug. 31.)

"We've had lots of interest from hunters," Idaho Fish and Game information supervisor Ed Mitchell said. The Idaho permits are scheduled to go on sale Aug. 24.

But a group of conservation groups that want the wolf returned to the federal endangered species list hope to block the hunting season before the week is through.

"We haven't made a final decision, but we'll make that this week," EarthJustice attorney Jenny Harbine said Monday about the 13 groups' legal strategy. "All my clients agree that at any level, hunting an imperiled wolf population is inappropriate."

Harbine said she didn't know whether the groups would request a federal court injunction to stall the hunting seasons in both Idaho and Montana, in just one single state, or pursue a different tack. But the groups maintain there aren't enough wolves to ensure populations in the two states can interbreed with packs in the more isolated Greater Yellowstone Area, which includes northwest Wyoming.

"With more aggressive state management, we expect that genetic connectivity would suffer," Harbine said. "We need wolves to travel from northwest Montana and Idaho into the Greater Yellowstone Area. They already have a hard time doing that."

The Montana Fish, Wildlife and Parks Commission set its own wolf quota at 75 animals in July. Its season starts Sept. 15 in four remote backcountry areas, with general hunting running from Oct. 25 to Nov. 29. If the 75-animal quota is not met, there's an option to extend the wolf season through December.

Montana has about 500 wolves and 40 breeding pairs. Federal rules require Montana to have at least 100 wolves and 10 breeding pairs.

Mitchell said Idaho has about 1,020 wolves within its borders. The hunting quota was set based on a "total mortality level" of wolves killed by natural causes, government-authorized hunters protecting livestock and big-game hunters.

"We're managing toward a goal of 2005-2007 (wolf population) levels," Mitchell said. "Hunting is an important factor, but it is one factor."

In Montana, FWP gray wolf program coordinator Carolyn Sime said the state quota was determined by estimating how many wolves could die from natural causes, government-authorized removals and hunting - without knocking the population out of balance.

Wolf packs that get too large are more likely to attack livestock, which triggers the removal of individuals or occasionally whole packs. Research indicates that some parts of the state are seeing declines in elk populations connected to increases in wolf numbers.

Wolves have been on the federal endangered species list since 1974. The Bush administration attempted to remove them from the list in Montana, Idaho and Wyoming in 2007 and 2008, but EarthJustice's coalition of conservation groups blocked that in court.

The Obama administration reconsidered the decision this spring, and agreed the wolf could be delisted in May.

However, Wyoming's wolves remain on the endangered species list because of objections to that state's proposed wolf hunting plans. Preliminary versions of the Wyoming plan would allow wolves to be shot on sight in 88 percent of the state.

U.S. Fish and Wildlife Service wolf coordinator Ed Bangs said the Idaho hunting plan announced Monday appears to fall within the expected range of state management options.

"The Service perspective is we strongly support public hunting," Bangs said. "It's been effective for controlling mountain lions and black bears. With the Idaho plan, there's no surprises from our point of view."

Reporter Rob Chaney can be reached at 523-5382, or rchaney@missoulian.com.