Gray wolves alter behavior of elk herds
By MIKE STARK, Billings Gazette Wyoming Bureau

PRAY -- The return of gray wolves to the Yellowstone ecosystem is changing how and where elk live and eat, researchers said at a conference here Tuesday. Much of the opening day's discussion at the 15th annual North American Interagency Wolf Conference at Chico Hot Springs was dominated by the interaction between wolves and elk in and around Yellowstone National Park. The three-day conference brings together wolf experts and researchers from around the continent, including contingents from Canada, Wisconsin, the Southwest and the northern Rocky Mountains.

Elk, wolf relationship

Several researchers from Montana State University and the University of Alberta at Edmonton gave presentations Tuesday examining the relationship between elk and wolves in the Yellowstone area. In studying 88 elk wearing radio collars before and after wolves were reintroduced, Julie Mao of the University of Alberta found that elk spread out across the landscape in the summer to decrease their chances of being killed by wolves. Wolves and their pups tend to stay close to their dens in the summer in the lower elevations, so elk tend to move to higher ground, Mao said. "This gives elk some protection from wolves at the higher elevations," she said.

The study also indicated that elk favor burned forests because there tends to be a good crop of forage there in the summer and wolves rarely venture into those burned-out spots. Once the weather turns cold and the snow starts, the dynamic changes and elk become more vulnerable to predation. "In the winter, elk and wolves are packed tightly together on the Northern Range," Mao said. The best defense for elk tends to be clustering in large groups on the open landscape. "That way, there are more eyes watching for predators," Mao said.

Additional studies

MSU's Eric Bergman is conducting a study to learn whether wolves go to areas where elk numbers are highest or where elk are most vulnerable. Preliminary results based on investigations of 272 locations where wolves have killed nonmigratory elk indicate that much of the killing, about 45 percent, happens in "environmental traps," Bergman said. Often, that means elk rush toward a river or creek to get away from wolves but find the water too shallow to stop the predators' advance, he said. In those cases, "the prey thinks they can get away but they really can't," Bergman said. The early data show that wolves take advantage of spots where elk might easily run into trouble, according to Bergman. Although wolves do kill elk that gather in large groups, it doesn't happen as often as might be expected, he said. Nathan Varley of the University of Alberta is developing computer models to determine how elk populations will be affected by wolves in the coming decades. As long as they share the same landscape, the two species will be inexorably linked, Varley said. As elk populations increase or decrease, wolf populations will follow. Elk populations will continue to fluctuate as they always have, sometimes widely, Varley said.

Living among wolves, Northern Range elk are expected to decline from an average population of about 14,000. One computer prediction, using current rates of wolf kills and other factors affecting elk, said the northern elk could vary from 5,000 to 16,000 over the next century, Varley said. The wolf population will regulate itself with the amount of food available, he said. "You can't just have infinite growth of wolves," Varley said. A computer modeling estimate showed that fluctuations in the northern elk herd could drive the number of wolves on the Northern Range to a low of 31 and a high of 140, Varley said.

Doug Smith, Yellowstone's wolf biologist, said that in the eighth year since wolves were reintroduced to the area, some new behaviors are appearing. Biologists are seeing more conflicts among wolves as the population grows by about 12 percent a year. Several new packs and subgroups have formed recently as more and more wolves intermingle. Some wolves have been seen with cuts on their muzzles that managers believe are the result of fights among wolves during breeding season, Smith said. "There's a lot of strife," he said. The cuts "are not something we've seen in previous years." Park officials tracking what wolves eat say that about 88 percent of the diet is elk, but only 14 percent are "prime age" for breeding. Most of the elk that are killed are calves or older cows or bulls, Smith said. "They are killing the weaker individuals," Smith said. On average in the early winter, one wolf kills an average of 1.4 elk every 30 days. In late winter, the number goes up to just over 2 per 30 days. By all accounts Tuesday, the wolf population in the Yellowstone area continues to thrive. The U.S. Fish and Wildlife Service is expected to request that gray wolves be taken off the Endangered Species List in the next year or two. Ed Bangs, FWS wolf recovery coordinator, told the audience that as the wolf population continues to grow and move toward more populated areas, more human-wolf conflicts will arise.

The days of wolves being a "cool" or "neat" novelty "is a little bit over now," he said. Government officials and private landowners may soon have more latitude to deal with problem wolves as they expand in range and number, and that could mean an increase in lethal control or harassment, Bangs said. "I think a lot of people are going to have a lot of problems with that," Bangs said. Nonetheless, the wolf population in the West is considered recovered and the delisting process needs to get under way, he said. Bangs acknowledged, though, that the process will most likely have to go through the court system. "This will certainly be litigated," he said.