Big cat behavior

Written by Dick Mason, The Observer December 03, 2010 05:05 pm

A single cougar would have no trouble keeping the freezers of half a dozen households filled with fresh meat.

Adult cougars kill a deer or elk an average of about once every seven days. At least they do in the Mount Emily Unit of Union and Umatilla counties, according to the preliminary results of a government cougar ecology and management study. The Oregon Department of Fish and Wildlife is conducting the study in cooperation with the Confederated Tribes of the Umatilla Indian Reservation, the Umatilla National Forest, the Wallowa-Whitman National Forest and many area land owners.

The predation study, which started 18 months ago, has involved about 30 cougars to which radio collars with GPS units were attached.

Preliminary results indicate cougars kill most frequently in June and July when they take an animal every 4.5 days. This is because many fawns and calves, born in May and June, are then available, said ODFW biologist Greg Davidson, a member of the study team.

Cougars make kills an average of only every two weeks in the winter. The rate is lower since cougars do not have to kill as frequently because:

• bears are sleeping, which means cougars are not competing with them for carcasses. Bears often eat cougar kills and sometimes even run big cats away from the deer and elk they have taken.

• meat does not spoil quickly in the winter. This means a cougar’s kills are preserved longer.

• fawns and calves, which are easy prey for cougars, are bigger than they were in the summer and fall. This means cougars have to kill fewer of them to get the nutrition they need, Davidson said.

Davidson and Darren Clark, an Oregon State University graduate student who is earning his Ph.D., spoke about the preliminary results of the cougar study Nov. 23 at a meeting of the Oregon Hunters Association in La Grande. Davidson and Clark are working under the direction of ODFW biologist Bruce Johnson, the study’s leader.

The researchers’ preliminary findings indicate, not surprisingly, that a high percentage of the elk and deer taken by cougars are fawns and calves. Seventy-nine percent of the elk the cougars killed have been calves and 49 percent of the deer have been fawns.

At least 90 percent of the animals the cougars are killing are deer and elk, Johnson said. Cougars overall are taking two deer for every elk they kill.

The majority of the adult deer and elk taken by cougars are does and cows. Adult bucks are killed much more frequently than adult bulls. Biologists have found only two instances in which a cougar took a branch-antlered bull elk, Davidson said.

Movement patterns revealed by tracking collars indicate that adult female cougars in the Mount Emily Unit have a territory of about 60 square miles and that adult males have a range about three times this. Additional information needs to be obtained before a more precise figure on the range of adult males can be obtained, Johnson said.

Biologists are currently monitoring 15 radio-collared cougars, but a total of 30 cougars have been collared over the course of the study. Seven cougars that were collared have died since the study started. Three were taken by hunters, two by state wildlife services damage control staff members, one by a vehicle collision and one died for unknown reasons.

Davidson said the most surprising thing abut the study to date has been how similar the preliminary results are to a cougar predation study conducted in Alberta, Canada, five to 10 years ago.

All of the cougars that have been collared in the Mount Emily Unit study were first treed by hounds run by Ted Craddock of La Grande. Tranquilizer darts were then fired by biologists at the mountain lions. They then fell from trees into nets or were lowered with the aid of ropes to the ground, where collars were attached.

Davidson said Craddock’s assistance has been instrumental to the study.

“He is fantastic,’’ Davidson said. “He is probably the best hounds man in Oregon.’’

Craddock also spoke at the OHA meeting. The hounds man said he has been tracking cougars and bears since 1954. Craddock has treed 1,524 cougars and bobcats and 2,465 bears since then.

Hunters in Oregon have not been allowed to use dogs to track cougars since late 1994 when voters passed a ballot measure banning this. Craddock was asked at the OHA meeting how he trains his dogs since they cannot be used to hunt cougars and bears in Oregon.

Craddock said he keeps his dogs in tracking mode via the many cougar projects he has assisted the ODFW over the years and by making an annual trip to California to hunt bears with his hounds. Hunting bears in California with dogs is legal. Cougar hunting in the state, however, has been illegal for two decades.

The Mount Emily Unit cougars Craddock treed for the ODFW are monitored by biologists who receive their radio collar signals during flights over the unit. The signals the biologists receive provide them with information on where the big cats have traveled in recent weeks.

Biologists then visit the sites the cougars have been at to determine what they have killed.

The study’s researchers will soon not have to make flights to determine cougar locations. Davidson explained that new collars that will send location information to a satellite will be attached to cougars. Biologists will receive the new location information via the satellite in the form of e-mails.

The Mount Emily Unit cougar study, which costs $180,000 a year, is expected to last about another 1.5 years.