In Idaho's rugged ranch country, a young calf killed by predators is every rancher's worst nightmare. For veteran biologist Rick Williamson, it's the beginning of a wildlife version of "CSI."
"There's a blood trail through here," Williamson observed. "We need to have the evidence to suggest what happened to this calf."
Wolves have been spotted in the region, but so have coyotes, bears and mountain lions. As part of his investigation, Williamson conducts a necropsy — an animal autopsy — right on the spot. If a wolf is responsible, the rancher will be compensated, and the wolf pack possibly hunted down.
"We are looking for feeding patterns that would suggest wolves [which] feed differently than coyotes or red fox or black bears," he said.
Such scenes are playing out across the northern Rocky Mountains as the growing wolf population — once endangered — leads to more and more conflict.
In the shadow of the Boulder Mountains, "Nightline" set out with Carter Niemeyer, a government scientist who's spent more than 20 years in the thick of the wolf debate.
Gray wolves once roamed freely in the West, and now they are back, stirring fear, stoking passion and inspiring awe.
Niemeyer says he isn't sure what it is about wolves that inspire such strong feelings.
"I have never really been able to put a handle on that," he said, "other than the lore, the mystique the fairy tales. … People talk about werewolves, little red riding hood, three little pigs."
By the 1930s, the wolf had been hunted, trapped and poisoned to near extinction, saved only by the Endangered Species Act. Then, in the mid-1990s, 66 wolves from Canada were reintroduced into the northern Rockies, and they now number about 1,500.
Niemeyer calls the resurgence of these wolves "one of the greatest conservation success stories that's ever been accomplished or achieved."
But that success also meant that, in late March, wolves lost their endangered status, making them fair game for ranchers and hunters. Now, age-old tensions again roil the West.
The Soulen family has raised livestock since 1929 on a sprawling ranch in western Idaho. Now, father and son run the ranch. It is hard, demanding work, branding lambs, docking their tails and preparing their flock for the annual 100-mile trek to a summer range up in the mountains. Last summer, some sheep strayed.
"We had about 150 head pull off from the band and they pulled up onto a ridge one night and bedded down," Harry Soulen said. "The wolves got into them and by the time the herder gathered up the remnants, we had lost 63 in that one incident."
Over the last three years, the Soulens say they've lost more than 800 head of sheep to wolves, which has had a "huge" impact on their livelihood.
"In a way it's a little bit like a thief or a shoplifter," Soulen said. "Each one of the incidents doesn't break you but day after day, night after night, you are losing sheep; after a while it adds up to some serious money."
Now, the Soulens and other ranchers have every right to kill wolves that threaten their livestock.
"We need to take wolves," said Harry's father Phil Soulen. "They need to be reduced. The numbers need to be reduced."
Harry Soulen said that the ideal number of wolves in the state of Idaho, from his perspective, would be "zero."
Since they lost federal protection, about 70 wolves have already been killed. But Idaho and other Western states are planning to permit the killing of hundreds more, allowing hunting for the first time in modern history. Environmentalists are asking a federal court to put wolves back on the endangered species list.
"Unfortunately, we hoped this would be a time for celebrating the recovery of wolves, and we know now that their future is really at risk," said Suzanne Stone, from Defenders of Wildlife.
Steve Nadeau of Idaho Fish and Game disagrees.
"If we are going to have wolves in the state, we are going to have wolf management, and sometimes that means lethal control and sometimes that means population management," he said. "They are not a benign creature. You can't just let them run loose and do what they want."
For hunters, who see wolves as competition for elk and other prized game, the relaxed state rules are welcome.
"I think it's necessary," said Brent Dunn, a hunter. "It's the only way we can annihilate a few of 'em. And it'll be a small portion compared to what's out there already."
Some Idaho hunters say they believe the season on wolves should last all year long, as it does right now in Wyoming.
"If you're lucky enough to see one in the woods, you should be able to shoot it, any time of year," said Greg Hill. "Not just in season. I'm not only a hunter, but I'm a rancher, too."
But not all ranchers feel so threatened. At a giant sheep operation in the Pioneer Mountain Valley, a concerted effort is under way to protect the livestock without killing wolves.
Mike Stevens, the president of Lava Lake Land and Livestock, believes that ranchers and wolves can coexist.
"We have seen the wolf numbers in our area increase dramatically since 2001," he said. "And we have really minimized the number of losses to wolves that we've experienced."
Some of their techniques are as old as the hills. The flocks are tended, day and night, by sheepherders and big guard dogs. But they also take advantage of technology, tracking wolves from their radio collars.
"It's an incredibly important tool for us because certainly the best proactive method is avoidance of the conflict in the first place," said Stevens.
And if wolves are nearby, the sheep are herded into pens specially rigged with solar powered electric fences, and fitted with flags.
"Our understanding is that wolves don't like the sight or sound of these fluttering flags," said Stevens.
Environmentalists consider this "nonlethal" approach a model that could be adopted across the West. But state officials doubt it could work across the wide open range.
"It's very, very expensive," said Steve Nadeau, the wolf program supervisor for the Idaho Department of Fish and Game. "You have to have people right on top of it chasing wolves around all the time. And it doesn't work all the time. It simply cannot work all the time. So that is a 'Polyanna'-type view of wolf management."
"People are starting to realize, wolves are back, and if we manage them well we can coexist with them," wolf advocate Suzanne Stone said. "We just need to learn how to do that. There need to be people willing on both sides to make that happen."
The states have agreed not to let their wolf populations drop below the bare minimum needed to sustain the species, but they must also juggle the human constituencies that have staked claims on the future of the wolf. And that may prove a far more difficult task.