McGRATH - Like a detective working a crime scene, state Fish and Game biologist Toby Boudreau knelt on the forest floor searching for hairs stuck to wild rose bushes. The victim, a mostly eaten moose calf, lay nearby.
The only parts left were its hide and a couple of ribs, part of the skull and a radio collar. The killer had even slurped meat from the hooves, leaving only eight empty cone-like tips.
Based on blond kinky hairs he found, Boudreau guessed the killer was a grizzly bear. But smaller scat piles and a single black hair suggested a black bear.
After stirring scat with a stick to look for moose remains, Boudreau noticed a bear trail. He followed salad bowl-size depressions across moss to the riverbank, where he found the clincher: paw prints in the mud so big they could only belong to a brown bear.
Chalk up another kill for the grizzlies.
Grizzlies are turning out to be unexpected calf-killers in a McGrath-area predator study by the Alaska Department of Fish and Game. The study is a key component of a predator control plan approved this spring.
The plan calls for state-sponsored wolf and even black bear killing if hunting and trapping don't cull enough predators.
Now managers have a third predator to consider - grizzly bears, and in particular several bears that seem to specialize in killing moose calves.
Grizzlies weren't part of the predator control plan.
"(Brown bear predation) is something we're going to have to wrestle with," Boudreau said. "We're discussing that right now."
Boudreau, the state's McGrath-area biologist, launched the study last month.
Preliminary results are surprising, and brown bears are the biggest surprise of all. Biologists thought the results would show wolves and black bears kill a significant number of calves in the spring, and that wolves take the lion's share of calves and adult moose in the winter.
Few biologists expected a heavy toll from grizzlies.
"People didn't really know how common grizzlies were in that area," said Pat Valkenburg, a Fish and Game research coordinator in Fairbanks who is supervising Boudreau's study. "It's showing us that the situation in McGrath is much more complicated than we thought it was."
The study has also shown that some brown bears have killed multiple moose, particularly in an area east of McGrath that appears to be one of the region's main calving grounds.
Grizzlies may even be traveling to the open muskeg area known as Pitka Flats specifically to eat newborn moose. Biologists don't know where those bears spend the rest of the year, or where the moose go after calving season. They don't know whether those moose are the same animals people hunt near McGrath.
"I bet you these bears are booking from 50 to 100 miles away to be there at this specific time of year," said Chip Dennerlein, who is not a biologist but serves on the governor's McGrath predator control task force.
Biologists collared 68 moose calves this May and June. So far, 32 have been killed: 15 by grizzlies, 11 by black bears and five by wolves. One drowned, according to Boudreau.
Dealing with brown bears is tricky. Given the controversy that erupts over wolf control, state-sponsored grizzly bear killing is almost unimaginable, Boudreau said.
Valkenburg said the state may relocate some of the more notorious calf-killers rather than begin killing brown bears.
"That's a place I don't think anyone wants to go," he said.