The population of the northern range elk herd in Yellowstone National Park has garnered a lot of concern over the years, based on having too many or too few elk. Today, the population of this largest herd in the park is way down, partly due to the reintroduction of wolves. However, wildlife biologists feel other factors are contributing.
When the park was created in 1876, concern centered on dwindling elk numbers due to poaching and market hunting. With protection given these elk, their numbers quickly climbed until concern centered on too many elk. Between 1920 and 1969, tens of thousands of elk were relocated or killed by park managers and hunters. In 1968, the concern had swung to worries of too few elk. The park changed to a more natural management style and from 1969-1994, elk numbers soared. Criticism then centered on elk destroying the park’s winter range.
The northern range elk herd used to winter inside the park. Due to large numbers of elk, many started leaving the park. The state of Montana began late-winter hunts in 1976 to limit numbers of elk wintering outside the park. These hunts removed an average of 965 elk each year. Hunting did not seem to hurt elk numbers and in January 1994, a record of 19,045 elk were counted inside the park.
Wolves were reintroduced that same year. In 2013, only 3,915 elk were counted, only slightly more than the 1968 low. Now, after 20 years of study, scientists know much of this is due to wolf predation but are not sure of the amount of their contribution to the decline. They feel other factors are limiting elk numbers. Some are natural like summer drought, winter severity, other predators and human hunting.
Half of wolf kills are elk calves. Of adult elk killed, most are more than 10-years old, leaving the most fertile young cows in the population. Calf kills are significant but scientists find wolves kill only 14-17 percent of the available elk calves and that the calves have a high survival rate during their first winter.
Further complicating the scene is the increase in numbers of park grizzlies, which along with black bears, are killing more elk calves. Cougar numbers are also up, although they do not kill a significant number of elk calves. Wolves are killing mostly elk, and bison numbers are increasing enough for concern they are competing with elk for food.
Along with much higher numbers of wolves, bears and cougars killing elk calves, human hunting has continued. From 1995-2002, late hunts annually removed between 940 and 2,465 total elk. In 1997, a bad winter forced many elk out of the northern park edge and hunters took 2,465 adult elk. Many elk died from winter conditions anyway, but this hunting may have contributed to the elk decline. Montana’s late hunts have been suspended and the regular season has only removed about 50 elk per year since 2010.
Wolves killing elk calves is the largest determinant of elk numbers. Hunters have complained that the park’s high numbers of predators are removing hunting opportunities outside the park.
The fate of the northern elk herd is in human hands and its future will be interesting. This elk population, like several other issues inside Yellowstone, comes down to competing visions of what the northern part of the park should look like.
This information comes from an article titled “The Challenge of Understanding Northern Yellowstone Elk Dynamics after Wolf Reintroduction” in the Yellowstone Science journal edition titled “Celebrating 20 Years of Wolves.” This journal is supported by the Yellowstone Association and Yellowstone Park Foundation.