The gray wolf was present in Yellowstone when the park was established in 1872. Today, it is difficult for many people to understand why early park managers would have participated in the extermination of wolves. After all, the Yellowstone National Park Act of 1872 stated that the Secretary of the Interior "shall provide against the wanton destruction of the fish and game found within said Park." But this was an era before people, including many biologists, understood the concepts of ecosystem and the interconnectedness of species. At the time, the wolves' habit of killing prey species was considered "wanton destruction" of the animals. Between 1914 and 1926, at least 136 wolves were killed in the park; by the 1940s, wolf packs were rarely reported. By the mid-1900s, wolves had been almost entirely eliminated from the 48 states.
An intensive survey in the 1970s found no evidence of a wolf population in Yellowstone, although an occasional wolf probably wandered into the area. A wolf-like canid was filmed in Hayden Valley in August 1992, and a wolf was shot just outside the park's southern boundary in September 1992. However, no verifiable evidence of a breeding pair of wolves existed. During the 1980s, wolves began to reestablish breeding packs in northwestern Montana; 50–60 wolves inhabited Montana in 1994.
In the 1960s, National Park Service wildlife management policy changed to allow populations to manage themselves. Many suggested at the time that for such regulation to succeed, the wolf had to be a part of the picture.
Also in the 1960s and 1970s, national awareness of environmental issues and consequences led to the passage of many laws designed to correct the mistakes of the past and help prevent similar mistakes in the future. One such law was the Endangered Species Act, passed in 1973. The US Fish and Wildlife Service is required by this law to restore endangered species that have been eliminated, if possible. By 1978, all wolf subspecies were on the federal list of endangered species for the lower 48 states except Minnesota. (National Park Service policy also calls for restoration of native species where possible.)
The US Fish and Wildlife Service 1987 Northern Rocky Mountain Wolf Recovery Plan proposed reintroduction of an "experimental population" of wolves into Yellowstone. An experimental population, under section 10(j) of the Endangered Species Act, is considered nonessential and allows more management flexibility. Most scientists believed that wolves would not greatly reduce populations of mule deer, pronghorns, bighorn sheep, white-tailed deer, or bison; they might have minor effects on grizzly bears and cougars; and their presence might cause the decline of coyotes and increase of red foxes.
In 1991, Congress provided funds to the US Fish and Wildlife Service to prepare, in consultation with the National Park Service and the US Forest Service, an environmental impact statement (EIS) on restoration of wolves. In June 1994, after several years and a near-record number of public comments, the Secretary of the Interior signed the Record of Decision for the final EIS for reintroduction of gray wolves to Yellowstone National Park and central Idaho.
Staff from Yellowstone, the US Fish and Wildlife Service, and participating states prepared for wolf restoration to the park and central Idaho. The US Fish and Wildlife Service prepared special regulations outlining how wolves would be managed as an experimental population.
Park staff completed site planning and archeological and sensitive plant surveys for the release sites. Each site was approximately one acre enclosed with 9-gauge chain-link fence in 10 x 10 foot panels. The fences had a two-foot overhang and a four-foot skirt at the bottom to discourage climbing over or digging under the enclosure. Each pen had a small holding area attached to allow a wolf to be separated from the group if necessary (i.e., for medical treatment). Plywood boxes provided shelter if the wolves wanted isolation from each other.
So far, data suggests wolves are contributing to decreased numbers of elk calves surviving to adulthood and decreased survival of adult elk. Wolves may also be affecting where and how elk use the habitat. Some of these effects were predictable, but were based on research in relatively simple systems of one to two predator and prey species. Such is not the case in Yellowstone, where four other large predators (black and grizzly bears, coyotes, cougars) prey on elk—and people hunt the elk outside the park. Thus, interactions of wolves with elk and other ungulates has created a new degree of complexity that makes it difficult to project long-term population trends.
The effect of wolf recovery on the dynamics of northern Yellowstone elk cannot be generalized to other elk populations in the Greater Yellowstone Ecosystem. The effects depend on a complex of factors including elk densities, abundance of other predators, presence of alternative ungulate prey, winter severity, and—outside the park—land ownership, human harvest, livestock depredations, and humancaused wolf deaths. A coalition of natural resource professionals and scientists representing federal and state agencies, conservation organizations and foundations, academia, and land owners are collaborating on a comparative research program involving three additional wolf-ungulate systems in the western portion of the Greater Yellowstone Ecosystem. Results to date indicate the effects of wolf predation on elk population dynamics range from substantial to quite modest.
Relocation and Release
Each wolf was radio-collared as it was captured in Canada. While temporarily penned, the wolves experienced minimal human contact. Approximately twice a week, they were fed elk, deer, moose, or bison that had died in and around the park. They were guarded by law enforcement rangers who minimized how much wolves saw of humans. The pen sites and surrounding areas were closed to visitation and marked to prevent unauthorized entry. Biologists checked on the welfare of wolves twice each week, using telemetry or visual observation while placing food in the pens. Although five years of reintroductions were predicted, no transplants occurred after 1996 because of the early success of the reintroductions.
Some people expressed concern about wolves becoming habituated to humans while in captivity. However, wolves typically avoid human contact, and they seldom develop habituated behaviors such as scavenging in garbage. Captivity was also a negative experience for them and reinforced their dislike of humans.
Results of the Restoration
The Role of the Courts
Legal Status of a Recovered Population
A legal challenge resulted in the Northern Rocky Mountain wolf population being returned to the federal endangered species list.
In 2011, wolf populations were again delisted in Montana and Idaho by an action of Congress, and a proposal by the US Fish and Wildlife Service to delist wolves in Wyoming was still pending. In 2012, a Congressional directive required the US Fish and Wildlife Service to reissue its 2009 delisting, which stated that ''if Wyoming were to develop a Serviceapproved regulatory framework it would be delisted in a separate rule'' (74 FR 15123, April 2, 2009, p. 15155).
On September 30, 2012, wolves in Wyoming began to be managed by the State under an approved management plan, as they are in the states of Idaho and Montana. The US Fish and Wildlife Service will continue to monitor the delisted wolf populations in all three states for at least five years to ensure that they continue to sustain their recovery. The US Fish and Wildlife Service may consider relisting the species, and even emergency relisting, if the available data demonstrates such an action is needed, as it does with all recovered species.
Wolves are now managed by the appropriate state, tribal, or federal agencies; management in national parks and national wildlife refuges continue to be guided by existing authorizing and management legislation and regulations.
Did You Know?
Lake trout are an invasive species of fish that is decimating the native cutthroat trout population in Yellowstone Lake.