Yellowstone National Park’s abundant carnivore population has meant a continued decline in the northern Yellowstone elk herd, according to a Feb. 18 aerial survey by the Montana Department of Fish, Wildlife and Parks and the National Park Service.
“Yellowstone is as predator rich as it’s been in 100 years,” said Doug Smith, Yellowstone’s wolf biologist, although the park's wolves number 83 this year, only 20 of which are living in the northern range.
“I think they’re low because there’s fewer elk,” he said.
The elk herd, much of which migrates into Montana in winter, declined 6 percent from a count of 4,174 last year to 3,915 this year. In recent years, the average decline was 8 percent. Also, more elk as a percentage of the herd – 77 percent – migrated out of the park than at any time in the past.
“In the old days, 30 percent would leave,” Smith said. “It could be there’s just more room out there to go into.”
The northern herd, which is only a portion of the park’s entire elk herd, has declined from a high of more than 19,000 before wolves were reintroduced into the park in 1995. Montana Fish, Wildlife and Parks also allowed an aggressive hunt for cow elk that migrated out of the park until 2005.
Smith noted that it’s also more difficult to count elk within the park these days because they are in smaller groups often hidden in the trees.
“In the old days, I’d see 300 to 500 elk out in the open,” he said. “That’s due to predation. A smaller herd is harder to find.”
Smith said park studies have shown the existing elk are “leaner and meaner,” with wolves killing fewer elk and shifting more of their attention to bison. Cow elk are getting pregnant at a rate of about 90 percent or higher, yet few calves are living to adulthood. Many are likely being eaten by bears, coyotes, mountain lions and even golden eagles.
Fish, Wildlife and Parks counted only 11 calves per 100 cows last year, said Karen Loveless, an agency biologist based in Livingston, Mont.
“That’s really poor,” she said. “As long as we have calf survival that low, I’m still really concerned.”
To maintain the elk population, she said, calf recruitment would have to double to about 20 percent. To increase the herd, the recruitment rate would have to rise to 30 percent. The northern herd has been below that 30 percent rate for more than a decade, she added.
“Our objective for northern range elk wintering in Montana is 3,000 to 5,000,” Loveless said.
Wolves have been blamed for much of the decline in the park’s elk numbers. Yet Smith noted that the northern range wolf population hasn’t been this low since 1996. The park’s wolf population peaked in 2003 at 174 animals. At the end of 2011, the number had declined to 98 wolves. Twenty Yellowstone wolves were shot by hunters when they ventured out of the park into Montana and Wyoming this hunting season.
Although Montana hunters would like to see more elk on the landscape, Loveless is busy right now scaring elk off agricultural lands in places like the Paradise Valley north of Yellowstone. The work is part of the state’s plan to keep elk, some of which carry the brucellosis bacteria, from mingling with cattle. The disease can cause an animal to abort.
Loveless said the department will hold a hunt to remove 10 elk in an attempt to disperse one group. On other property, the department is helping to repair fences, fencing haystacks and firing nonlethal cracker shells to scare elk away from cow feeding areas.
Loveless said the herds of elk vary from groups of 100 up to 600 on different ranches. The work will continue until June 15, which is considered the end of the time when bacteria transfer between the species is likely to occur.