Dogs and biologists track collared cougars in northeast Oregon
Darren Clark Radio-collared cougars in northeast Oregon help biologists track their numbers and their diets.
The estimated number of deer and elk killed by cougars is a hot button for hunters, and researchers now believe man's best friend and modern science will help with the specifics. The key is to find the true number of cougars in the state.
"One (deer or elk) a week is about right," said Bruce Johnson, project leader for the Oregon Department of Fish and Wildlife's Mt. Emily cougar study. "I think they're having an effect, but what we don't know yet is at what level."
That's largely because the current estimate of cougar numbers in Oregon (5,700) is just that: an estimate.
Johnson and his team of researchers, including faculty and graduate students from Oregon State University, are monitoring a dozen active radio collars around the necks of live cougars in the Mt. Emily game management unit, between La Grande and Pendleton. Since their study began in winter 2008, 35 have been collared and watched. Many died of various causes (one was killed by another cougar) or left the area. A few collars failed, leaving the current mix.
The team also uses two trained dogs, a border collie and a lab/pointer mix, to help find cougar kills. Cougars spend time at their kills, established by repeat positions on the radio collars. Researchers note the clustered dots and take the dogs to the sites.
The dogs are far more efficient than humans at finding scat and remains, often buried or dragged off and, especially, hidden beneath winter snow. They're rewarded at each site with several minutes of playing time with a tennis ball.
Researchers scrutinize what they find, analyze its DNA and use the information to develop formulas that may lead to more accurate estimates of cougar numbers living within the unit.
The formulas may then be overlaid across other parts of the state for more accurate total numbers of cougars and their overall effect on deer and elk herds.
Meanwhile, the study is also producing a wealth of information about cougars and what they eat:
Deer (66 percent of kills) are preferred, followed by elk (29 percent) and non-ungulates (i.e., coyotes, raccoons, etc., 5 percent). Male cougars tend to prey on elk more frequently than female cougars.
Most of the deer (47 percent) were fawns.
No cattle or horses have been killed by collared cougars during the study.
Buck deer are killed most frequently between August and November, when they're least vigilant, either due to noisily rubbing velvet off antlers or in the rut, when bucks lose much of their natural caution.
Female cougar predation on elk is heavily focused on elk calves (86 percent of elk they kill). In general, male cougars kill larger elk.
Predation on large bulls is relatively rare, almost always by male cougars, which more commonly kill smaller bulls. Only a few bulls were killed by female cougars and those during early spring, when they're without antlers.
Non-ungulate prey included badger, beaver, black bear, raccoon, coyote, domestic cat and dog, domestic sheep, opossum, snowshoe hare and wild turkey.
Scavenged animals (already dead) included road-killed deer and elk, hunter kills, kills by other cougars, cattle remains, a black bear carcass and an illegal bear bait. Nearly half of the scavenged sites were by the same cougar.
Johnson said there's nothing wrong with licensed hunters (with a tag) shooting a radio-collared cougar.
"It's part of the overall picture of mortality causes for cougars," he said. "We just ask that they (hunters) not shoot the cougar through the collar."
Details are online at: https://sites.google.com/
site/mtemilycougarstudy/
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