U. of Montana Biologist Mark Hebblewhite has been seeking answers as to why Elk calves on the Idaho side of the Bitteroot Mtns. are perishing at a faster pace than their cousins across the State line in Montana.............Bears and Cougars are the key predators of Elk fawns in the first weeks post birth..............Wolves take calves at a later life-stage(6 or so months later during the Winter Months) and are not sizeable limiting agents during Spring birthing season

Bitterroot elk calves survive at higher rate than Idaho counterparts, study says

HAMILTON - Elk calves in the Bitterroot Valley may be better at hiding than their cousins in Idaho.
Or it could be that there are fewer black bears living on this side of the border. Maybe this spring's miserable weather had something to do with it.

For whatever reason, 66 elk calves captured and radio-tagged this spring as part of a major research project in the southern reaches of the Bitterroot have so far survived at a higher rate than their compatriots involved in similar studies in Idaho and elsewhere across the West.

At last count, 24 calves had died, or nearly 40 percent. In similar studies right across the Idaho line, about half the tagged elk calves succumbed within the first couple of months of their lives."The survival rate here was higher than expected," said University of Montana assistant wildlife biology professor Mark Hebblewhite. "Just over the border in Idaho, they found that there was quite a bit of mortality during the hiding phase of an elk calf's life. They are quite vulnerable then."

After an elk is born, its mother hides it away in hopes that nothing will find it before the calf is strong enough to run away on its own. In Idaho, black bears in particular key in on the newborns."The elk calves here weren't hit quite as hard in that first pulse," Hebblewhite said. "Why is that? We don't know. Maybe there are fewer bears here than in Idaho."

That's just one of the questions raised during this first year of an ambitious three-year study of elk population dynamics in the southern Bitterroot. After tagging the newborn calves this spring, researchers used t he radio tags to guide them to the carcasses of newly killed elk calves in an effort to document the reasons for their deaths.

So far bears and mountain lions are the main culprits. Cougars have killed seven and bears were responsible for five. Researchers have documented one wolf kill. Four of the calves died of natural causes. Six more deaths are undetermined.

"In some cases, we only found an ear or other small pieces," Hebblewhite said. "As the elk calves get bigger, they attract more predators when they die. ... This is like wildlife CSI. We don't always catch who did it."Bear and mountain lion predation on newborn elk calves is consistent with findings of other studies. Wolves tend to focus more on elk calves during the winter months.

To ensure the study obtains a clear picture on winter calf mortality, researchers are preparing for the possibility that they will need to capture some more youngsters in December."That's often the problem with calf survival studies," Hebblewhite said. "They all die and then you don't have enough tagged animals to provide a good sample size."

Funding for the research project continues to trickle in from a variety of mostly private sources.
"In general, things are looking good on the funding front," said Kelly Proffitt, the state's lead research biologist for the Bitterroot study. The Rocky Mountain Elk Foundation, Safari Club International, Ravalli County Fish and Wildlife Association, Montana Bowhunters, Pope and Young, and Bitterroot and Beaverhead RAC groups have contributed to the effort. A $100,000 McIntire-Stennis U.S. Department of Agriculture research grant has helped pay for the university-based portion of the research.
The study is being conducted through a partnership between Montana Fish, Wildlife and Parks and the University of Montana.

The capture portion of the operation is the largest expense.The state has contracted with a helicopter wildlife capture crew based out of Salt Lake City. It charges between $650 and $700 to capture an elk.
"It's the safest way to catch an animal, but it is expensive," Proffitt said.

Last winter, the crew captured and radio-collared 44 cow elk in the east and west forks of the Bitterroot. Since then, researchers have documented some fairly lengthy migrations, especially between French Basin and the Big Hole Valley. One cow has moved past Wisdom and into the Fishtrap Creek area.
"They have certainly spread out," Proffitt said. "Our telemetry flights are getting longer and longer."

Four cows have died so far.One was killed by a mountain lion. Another died of unknown causes. Two older animals died of natural causes this spring. Both were in poor body condition after a difficult winter.
"We've learned quite a bit so far," Proffitt said. "We didn't have real strong expectations going into this study and so I can't say that anything has been really surprising."

With the funding nearly locked up for the three-year elk study, Proffitt said the group is considering adding a wolf and lion component into the mix.The proposal calls for trapping additional wolves in the study area next summer to get a better idea of wolf densities and pack size."Getting a good lion density estimate is more challenging," Proffitt said.A recently completed study in the Garnet area that used dogs to tree lions and air-powered dart guns to collect DNA samples used to develop a population estimate could be duplicated in the Bitterroot."We will start fundraising for both those projects in the near future," she said.