Northern Rocky Mountain wolves, a subspecies of the gray wolf ( Canis lupus ), were native to Yellowstone when the park was established in 1872. Predator control was practiced here in the late 1800s and early 1900s. Between 1914 and 1926, at least 136 wolves were killed in the park; by the 1940s, wolf packs were rarely reported. By the 1970s, scientists found no evidence of a wolf population in Yellowstone; wolves persisted in the lower 48 states only in northern Minnesota and on Isle Royale in Michigan. An occasional wolf likely wandered into the Yellowstone area; however, no verifiable evidence of a breeding pair of wolves existed through the mid 1990s. In the early 1980s, wolves began to reestablish themselves near Glacier National Park in northern Montana; an estimated 75 wolves inhabited Montana in 1996. At the same time, wolf reports were increasing in central and north-central Idaho, and wolves were occasionally reported in the state of Washington. The wolf is listed as endangered throughout its historic range in the lower 48 states except in Minnesota, where it is threatened.
National Park Service (NPS) policy calls for restoring native species when: a) sufficient habitat exists to support a self-perpetuating population, b) management can prevent serious threats to outside interests, c) the restored subspecies most nearly resembles the extirpated subspecies, and d) extirpation resulted from human activities.
The U.S. Fish Wildlife Service 1987 Northern Rocky Mountain Wolf Recovery Plan proposed reintroduction of an experimental population of wolves into Yellowstone. In a report to Congress, scientists from the University of Wyoming predicted reductions of elk (15%-25%), bison (5%-15%), moose, and mule deer could result from wolf restoration in Yellowstone. A separate panel of 15 experts predicted decreases in moose (10%-15%) and mule deer (20%-30%). Minor effects were predicted for grizzly bears and mountain lions. Coyotes probably would decline and red foxes probably would increase.
In October 1991, Congress provided funds to the U.S Fish Wildlife Service (USFWS) to prepare, in consultation with the NPS and the U.S. Forest Service, an Environmental Impact Statement (EIS) on restoring wolves to Yellowstone and central Idaho. After several years and a near-record number of public comments, the Secretary of Interior signed the Record of Decision on the Final Environmental Impact Statement (FEIS) for reintroduction of gray wolves to both areas. Staff from Yellowstone, the USFWS, and participating states prepared to implement wolf restoration. The USFWS prepared special regulations outlining how wolves would be managed as a nonessential experimental population under section 10(j) of the Endangered Species Act. These regulations took effect in November 1994. As outlined in the Record of Decision, the states and tribes would implement and lead wolf management outside the boundaries of national parks and wildlife refuges, within federal guidelines. The states of Idaho, Wyoming, and Montana have begun preparation of wolf management plans.
Park staff assisted with planning for a soft release of wolves in Yellowstone. This technique has been used to restore red wolves in the southeastern United States and swift fox in the Great Plains and involves holding animals temporarily in areas of suitable habitat. Penning of the animals is intended to discourage immediate long-distance dispersal. In contrast, a hard release allows animals to disperse immediately wherever they choose, and has been used in Idaho where there is limited access to the central Idaho wilderness.
In the autumn of 1995 at three sites in the Lamar Valley, park staff completed site planning, and archaeological and sensitive plant surveys. Approximately 1 acre was enclosed at each site with 9-gauge chain link fence in 10' x 10' panels. These enclosures could be dismantled and reconstructed at other sites if necessary. The fences had a 2' overhang and a 4' 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 for medical treatment. Inside each pen were several plywood security boxes to provide shelter. For the 1996 release, one pen was relocated to Blacktail Plateau and another was constructed in the Firehole Valley in central Yellowstone. Subsequently pens have been relocated from Lamar to other areas in the park interior to facilitate releases into other geographic areas or the park or special circumstances that require the temporary penning of wolves.
USFWS and Canadian wildlife biologists captured wolves in Canada and released them in both recovery areas in 1995 and 1996. As planned, wolves of dispersal age (1-2 years old) were released in Idaho, while Yellowstone released pups of the year (7+ months old), together with one or more of the alpha pair (breeding adults). Young pups weigh about 75 lbs. and are less likely to have established a home range. The goal was to have 5-7 wolves from one social group together in each release pen.
Each wolf was radio-collared when captured in Canada. For about 8-10 weeks while temporarily penned, the wolves experienced minimal human contact. Approximately once each week, they were fed roadkills. They were guarded by rangers and other volunteers who minimized the amount of visual contact between wolves and humans. The pen sites and surrounding areas were closed and marked to prevent unauthorized entry. Biologists used radio-telemetry to check on the welfare of wolves.
Although concern was expressed about the wolves becoming habituated to humans or to the captive conditions, the temporary holding period was not long in the life of a wolf. In Alaska and Canada, wolves are seldom known to develop the habituated behaviors seen more commonly in grizzly bears. Wolves, while social among their own kind, typically avoid human contact. They are highly efficient predators with well-developed predatory instincts. Their social structure and pack behavior minimizes their need to scavenge food or garbage available from human sources. Compared to bears, whose diet is predominantly vegetarian, wolves have less specific habitat requirements. The wolves' primary need is for prey, which is most likely to be elk, deer, and other ungulates in these recovery areas.
In 1995, fourteen wolves were released into Yellowstone National Park. In 1996, seventeen more wolves were brought from Canada and released. After release, several thousand visitors were lucky to view wolves chasing and killing elk or interacting with bears during spring. A park ranger and a group of visitors watched a most exciting encounter between two packs which likely resulted in one young wolf's death. This was not the first fatal encounter between wolves, although human-caused mortalities still outnumber inter-pack strife as a cause of wolf deaths.
Yellowstone's first fourteen wolves bore two litters totalling nine pups. In 1996, four packs produced fourteen pups. After the wolves' release in 1996, plans to transplant additional wolves were terminated due to reduced funding and due to the wolves' unexpected early reproductive success.
In early 1997, ten young wolves, orphaned when their parents were involved in livestock depredation on the Rocky Mountain Front in northwestern Montana, were released into the park. In the spring of the wolf restoration project's third year, nine packs of wolves produced 13 litters of 64 pups. Three of the packs produced multiple litters which, while documented in the literature, is still unusual. Alpha male wolves generally do not breed with their own offspring, possibly to prevent inbreeding. However, as wolves were matched up during temporary periods of penning and as pack members shifted or were killed and replaced by other dispersing wolves, the occasional result has been packs in which one or both of the alpha pair were not the parents of subordinate pack members. Consequently, the alpha males probably had less incentive to breed with only one female, especially since food was abundant and the packs were still in the early stages of establishing their territories. Lone wolves continued to roam widely, but most of the wolves remained primarily within the boundaries of Yellowstone National Park
An estimated 100,000 park visitors have observed wolves since their return in 1995. The program's visibility has resulted in opportunities to educate audiences about predator-prey relationships, endangered species restoration, and the importance of maintaining intact ecosystems. The program has also generated numerous partnerships with private groups and individuals who generously donated their time and money-critical in an era of reduced budgets and staff downsizing.
For both Idaho and Yellowstone, wolf population recovery is defined as having about 100 wolves, or approximately 10 breeding pairs, established in each area for 3 successive years. The goal to restore wolves and begin delisting them by approximately 2002 appears within reach. The return of the only species known to be missing from the world's first national park for the past half-century has been a milestone in ecological restoration. It has not only restored the wildlife complement of greater Yellowstone; it has been a symbolic victory for conservationists who patiently and persistently reversed the once-dominant attitude against predators to one of acceptance. We believe that Aldo Leopold would be proud that so many humans have come to respect even these killer creatures with whom we share the Earth. The Yellowstone Park Foundation raises money each year to help support Yellowstone's Wolf Project. They are a non-profit organization whose mission is to fund projects and programs that protect, preserve and enhance Yellowstone National Park.