Wolf History, Conservation, Ecology and Behavior
Wolfology Item # 366
v5, n1 (March 1997)

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Planning and Implementing a Reintroduction of Wolves to Yellowstone National Park and Central Idaho
S.H. Fritts, E.E. Bangs, J.A. Fontaine, M.R. Johnson, M.K. Phillips, E.D. Koch, J.R. Gunson
The Northern Rocky Mountain Wolf Recovery plan proposed reintroduction of Canis lupus (gray wolf) to Yellowstone National Park and central Idaho as part of a wolf restoration plan for the northern Rocky Mountains of the United States. Strong opposition from some factions within the region forestalled the action for two decades....A reintroduction plan was developed in the summer and fall of 1994. Acquiring, holding, transporting, and releasing suitable wolves for reintroduction presented a myriad of technical and logistical challenges....The progress of the reintroduction program in its first year far exceeded expectations....Future reintroduction planners can expect sociocultural issues to pervade the effort, but they can be optimistic that, from a biological standpoint, reintroduction of wolves has strong potential as a restoration technique.
Background and Introduction
Restoration of endangered animals to former range often involves complex biological, social, and political challenges. After two decades spent overcoming such obstacles, Canis lupus (the gray wolf) was reintroduced into Yellowstone National Park and central Idaho in January 1995. The purpose of this paper is to provide others who may contemplate similar programs with the benefit of our experience in obtaining approval for, planning, and carrying out a reintroduction of wolves. In addition, we provide the first biological results of our reintroduction design and protocol as an evaluation of its efficacy....
....The majority of settlers to North America originated in areas of Europe where the views on wolves were most negative. Apparently, most viewed the animal as symbolic of an untamed land that had to be subdued in the name of civilization. Beginning in the eighteenth century, the wolf was eliminated from all of the contiguous United States except for northeastern Minnesota....Apparently, no viable wolf population remained anywhere in the area of Yellowstone National Park and central Idaho by about 1925. Hardly anyone had objected and future restoration seemed highly improbable. The reputation of the wolf as a vicious killer of livestock and big game and a threat to human safety lived on in legend within the northern Rockies. Such attitudes are still among many residents of the area, particularly livestock producers.
Origins of Interest in Wolf Restoration
A few wolves (<10) were killed from the 1940s through the 1970s in Montana, Idaho, and the greater Yellowstone area. The individuals killed were probably dispersers from breeding populations in Canada about 400-700 km to the north. During the mid-1900s, biological and social conditions for the potential return of wolves to the region improved. As modern wildlife management was implemented, ungulate populations rebounded from their lows near the turn of the century. Production of domestic sheep declined, and so did the intensive predator control associated with that industry, especially the widespread use of poison baits. The number of people living in rural areas declined....Vast tracts of federal land were protected from human development by being designated as national parks, national forests, and (later) as wilderness. As early as the 1940s, Aldo Leopold, champion of professional wildlife management, proposed restoration of wolves to Yellowstone. By the late 1960s...the wolf's negative image had moderated somewhat, partly because of knowledge gained from scientific studies of the animal. Also, changing values resulted in Americans becoming more interested in preserving large predators and the natural ecosystems on which they depend. Nonetheless, the closest breeding population of wolves to the northwestern states continued to be hundreds of kilometers to the north in Canada, and the chances for natural recolonization still appeared low.
The [Endangered Species Act (ESA)] brought federal protection to the remaining gray wolves in the lower 48 states and a federal mandate to return the species to a secure recovery level that would allow its removal from protection under ESA. The northern Rockies of the U.S. was identified as one region where wolves should be recovered. The U.S. Fish and Wildlife Service appointed a Northern Rocky Mountain Wolf Recovery Team that developed a plan for recovery. The plan identified three areas -- northwestern Montana, central Idaho, and the greater Yellowstone area, totaling about 69,000 km2 -- where wolves could be restored, based upon ample prey, sufficient land in public rather than private ownership, and a low potential for conflicts with human economic activities. According to the plan, and to more recent analyses, restoration of 10 breeding pairs of wolves to each of the three areas would create a metapopulation that would be fully viable. Interchange of wolves among the three main recovery areas would regularly occur, and connectivity with the Canadian population to the north would be assured via the population in northwestern Montana. After the recovery-level populations had been reached (total of about 300 wolves) and maintained or exceeded for 3 consecutive years, the species would be removed from ESA protection and managed by state and tribal wildlife agencies. Two other gray wolf recovery programs, guided by their own recovery plans, exist outside the northern Rockies, one in the upper Midwest and the other in the southwestern states.
The recovery plan for the northern Rockies recommended (1) that natural recovery be encouraged in northwestern Montana, (2) that consideration be given to reintroducing wolves into Central Idaho if two packs were not found there by 1992, and (3) that wolves be reintroduced to Yellowstone because that recovery area seemed too distant from the other areas for natural recolonization to occur within the next few decades. The recovery plan recommended that reintroduced wolves be given the special designation of "experimental" under Section 10(j) of the ESA, which would allow more flexible management of them and could reduce local concerns and opposition to their restoration. Even so, they would continue to be protected by the ESA until recovery goals had been reached and they were delisted....
....In 1986 a pack produced pups in Glacier National Park in Montana, and soon a small population became established along the international border. By 1993 about 87 wolves occupied northwestern Montana and adjacent extreme southeastern British Columbia, including an increasing number that were surviving outside the designated recovery area in Montana where livestock are present.
Wolves that naturally recolonized northwestern Montana killed livestock as early as 1987; since then depredations have averaged 3 cattle or less and 2 sheep or less per year. Although few in number, these depredations received so much attention by the news media that the public received a false impression about the importance of wolves as livestock predators. The wolf was perceived by livestock producers as a major threat in the northern Rockies during the 1980s and 1990s, making public acceptance of wolf restoration in each of the three recovery areas far more difficult to achieve.
....The suggested wolf reintroduction to Yellowstone became an issue of widespread public interest during the late 1980s. From 1987 through 1990 bills were introduced in Congress to reintroduce wolves in Yellowstone, but none were passed....Political pressure by elected officials from Wyoming, Montana, and Idaho successfully delayed decisive restoration actions in Yellowstone and Idaho until late 1991....
The Environmental Impact Statement
In November 1991 Congress directed the U.S. Fish and Wildlife Service...to prepare an environmental impact statement (EIS) on wolf reintroduction to Yellowstone and central Idaho and provided funding for the project. An EIS is a legally binding, federal planning process that is required by the National Environmental Policy Act of 1969. It is a logical step-by-step process that involves the public in determining the potential effects of, and balancing conflicting biological and social aspects of, federal actions that significantly affect the quality of the human environment. An EIS identifies the problem, defines what information is required to make an informed decision to solve the problem, lists the significant issues to be resolved, provides a reasonable range of alternatives for solving the problem, and recommends the action that will best solve the problem....
An interagency team led by the USFWS conducted the EIS. The first phase occurred in the spring of 1992; it included 34 informal, nonstructured public meetings ("open houses") in which citizen input and one-on-one exchanges with agency personnel were offered. These meetings served to identify issues relating to wolf reintroduction that were of greatest interest and concern to the public. The 34 meetings attracted 1730 participants. In addition, about 4000 written comments were received....The next phase was identification of wolf management options to deal with the issues that were identified earlier. That phase consisted of 27 more open houses, 6 formal hearings attended by some 2000 people in August and September 1992, and receipt of some 5000 additional written comments.
The draft EIS, completed in June 1993, contained five alternatives for resolving the restoration issue. Three of these involved reintroduction to Yellowstone and central Idaho; one was to rest the policy on an eventual natural recolonization of wolves regardless of how long that took, and the fifth was to act in opposition to having wolves in Yellowstone and central Idaho, even if they appeared there through natural dispersal. The alternative recommended by the USFWS in the draft EIS was to reintroduce wolves to both Yellowstone and central Idaho. The wolves were to be designated "nonessential experimental" and would be reintroduced only if two or more naturally occurring wolf packs were not located in either area before October 1994....
During development of the draft EIS, potential impacts of wolf restoration on the Yellowstone and central Idaho recovery areas...were predicted from detailed studies. The Yellowstone area is about 64,750 km2, with 76% in federal ownership and 21% in private ownership. Yellowstone National Park is at the center, consisting of 9,000 km2, and is surrounded by six national forests. This area has over 95,000 ungulates and an annual hunter harvest of 14,300 ungulates, is grazed by about 412,000 livestock, has a $4.2 billion (U.S.) local economy, and receives about 14.5 million recreational visits a year. The central Idaho area is about 53,613 km2 (nearly all U.S. Forest Service land), has about 241,400 ungulates and a hunter harvest of 33,400 ungulates, is grazed by about 306,500 livestock, has a $1.43 billion local economy, and receives about 8 million recreational visits annually. Human density in the two areas averages 2.0 per km2 and 1.0 km2 respectively. The centers of both areas are not used for livestock production. Estimates in the EIS concluded that in the Yellowstone recovery area a minimally recovered wolf population (about 100 wolves) would kill about 20 cattle (1-32), 70 sheep (17-110), and up to 1200 wild ungulates each year. Wolf recovery would increase visitor use and generate an estimated >$23 million in economic benefits annually. In central Idaho, a minimally recovered wolf population of about 100 wolves would kill an estimated 10 cattle (1-17), 60 sheep (32-92), and up to 1650 wild ungulates per year.
The final EIS was approved 14 April 1994....The objective...was to establish viable wolf populations by the year 2002 while managing the wolves to the greatest extent possible under the ESA in order to tend to the needs and concerns of people who live in the restoration areas. The "experimental" designation would allow certain actions to deal with problems caused by the wolves....The most noteworthy of the special management provisions proposed in the EIS was to allow livestock owners and their agents to shoot wolves caught in the act of killing livestock on their own private land, and, in special circumstances, on public lands.
During the 32 months of public input on the EIS, over 130 public meetings were held, about 750,000 EIS documents distributed, and some 170,000 comments received from the public. Comments were received from every state in the U.S. and from more than 40 other countries. The comments reflected the strong polarization that has plagued management of wolves and were consistent with our belief that most wolf recovery issues have more to do with deeply held personal values about government, influences of people living outside the region, people's relationship to nature, and the political role of special interest groups, than with wolves themselves....
The proposal to reintroduce wolves even aroused disagreement among wolf recovery advocates about whether wolves should be reintroduced or allowed to recolonize those areas naturally, even if the latter option required many additional years. Some individuals and organizations believed that small wolf populations already occupied Yellowstone and central Idaho, and the death of a wolf in central Idaho in 1991 and another near Yellowstone in 1992 reinforced that belief. Previously, a lawsuit had been filed to stop reintroduction to Yellowstone based on the conviction that a small population of "original" wolves still exists there, and that placing Canadian wolves among them would eradicate the unique gene pool. In addition, on 5 January 1995 the Sierra Club Legal Defense Fund filed a lawsuit on behalf of four organizations against reintroduction of wolves into Idaho, arguing that reintroducing wolves using the "experimental population" provision would reduce the full ESA protection of wolves that they believed already occupied Idaho....
The recommendation in the final EIS to reintroduce wolves was based on the following convictions and reasoning: (1) although single dispersing wolves occasionally were reaching the Yellowstone and central Idaho areas, breeding was not occurring, and population establishment was not imminent; (2) population goals for removal from the list of endangered species would be reached faster, and state and tribal management would occur earlier with reintroduction; (3) recovery would be less expensive over the long term because recovery goals would be reached sooner; (4) genetic variability in the potential Yellowstone and Idaho subpopulations would be greater if wolves were reintroduced from different populations and genetic backgrounds; (5) reintroduced wolf packs were more likely to settle in places where the potential for conflict with humans was lowest; and (6) establishment of a fully viable metapopulation composed of three healthy subpopulations would occur faster and more synchronously if the Yellowstone and Idaho subpopulations were established immediately.
The final step in the EIS process was the Secretary of the Interior signing the Record of Decision on 15 June 1994. This action provided Department of Interior approval to proceed with the EIS-proposed reintroduction of wolves designated as "nonessential experimental."....
Developing the Reintroduction Protocol
In the final year of the EIS development we began to consider how a reintroduction could be devised and conducted....Aside from the C. rufus (red wolf) program that uses animals of captive origin, proven methodology for reintroducing wolves was almost nonexistent. Previous work indicated that translocated wolves tend to separate and travel widely but can survive unless killed by people, and they are capable of finding one another, of pair bonding, and of breeding. Because one-time reintroductions inherently seemed more likely to fail, we decided early that repeated infusions should occur over a period of years until a breeding population was established. Based on available information, we expected major difficulty in inducing the wolves to settle and establish breeding packs in the areas where released.
A series of questionnaires was sent to 53 biologists who have worked with wolves in the wild and in captivity in order to obtain their opinions on how to reintroduce wolves. Opinions of the 31 who responded differed greatly on even the most fundamental variables....
Several key decisions had to be made before most preparations for the reintroduction could proceed. Examples included where to obtain the wolves; whether to radiocollar and monitor wolves from the donor population prior to removal for reintroduction; the type of release (slow or quick); the time of year of release; the number, age, and breeding status of wolves to be used (pups, yearlings, adults, entire packs); and the duration of acclimation, if a slow release were used. There were a myriad of other issues to explore and decisions to be made as soon as possible, such as capture methods (traps, live-snares, darting from helicopter, or net gunning from helicopters); where and how to hold wolves before shipping; how to transport wolves (truck, commercial airline, contracted aircraft); which permits were needed; what to feed wolves during holding, transport, and at release; which immobilizing drugs to use for different phases of the operation; and how to protect wolves from people while they were in captivity. Other specific factors we considered when planning were cost; effect of wolf removals on the donor population; whether to use wolves that were already pair-bonded or attempt to force the pair-bonding of adult wolves after capture; likelihood of breeding in captivity;....climate and physiology of capture and release sites; whether to conduct reintroductions into Yellowstone National Park and central Idaho concurrently; the number of years over which releases would be necessary to establish a population in each area....
The potential for transporting infectious diseases with the wolves was examined by the project veterinarian. We decided early that wolves would be taken from areas where significant diseases such as tuberculosis, brucellosis, and terrestrial rabies were not present....In addition, we would give careful attention to the comfort and well-being of the wolves to minimize physiological and psychological stress....
....The media would be given access to essentially every phase of the operation, provided that their activities did not interfere with the safety of the wolves and the project personnel....We were well aware that any mistakes would be well publicized and that public perception of inadequate planning or animal care would result in strong criticism of the program that could result in its termination.
Final Reintroduction Design
Working with Canadian provincial authorities, we developed plans to capture wolves from areas of British Columbia and Alberta with mountain-foothill habitat where elk and deer were available as prey. Alberta has about 4200 wolves and British Columbia about 8000, with about 11% killed annually by humans in each province. Populations are believed to be increasing in the southern portions of both provinces. Wolves from southwestern Canada are of the same genetic stock as wolves now colonizing northwestern Montana....Also, we knew from discussion with Canadian biologists that wolves from those areas would be accustomed to killing the major prey available in Yellowstone and central Idaho (elk and deer), would be from terrain similar to that of the release areas, and would have little if any exposure to livestock....
Ideally, the capture areas would have enough treeless landscape to make helicopter darting possible and would be accessible by fixed-wing aircraft or ground vehicles to facilitate transport of the wolves out of the area. Darting was the only method that would provide assurance that captured wolves were from the same pack because they would be observed together at the time of capture or possibly during monitoring work before capture.
....Responses by biologists to the survey on how to release wolves generally fell into two basic schools of thought: slow release and quick release. Each approach offered some distinct advantages and disadvantages. For the first year of the multi-year project we decided to try an experimental approach that would incorporate the core principles of the two divergent strategies and conduct different types of releases in Yellowstone and central Idaho. For Yellowstone, we prepared to hold and acclimate small to moderate-sized packs (4-7 individuals) that ideally included the breeding (alpha) female or pair and pups of the year. The alpha wolves presumably would be more likely to remain together after release because they were already pair-bonded. For central Idaho we would transport and immediately release (without conditioning in holding pens) non-breeding members of packs that were young adults and yearlings -- individuals of prime dispersal age. Although this procedure would likely result in initial separation and extensive movements, we reasoned that it would to a degree replicate the process by which pack formation naturally occurs....Translocated wolves that do not return home eventually revert to lone wolf-disperser behavior and can survive alone, as well as find mates and establish packs....Quick releases have been the most common techniques for wildlife reintroduction throughout North America, albeit with variable success.
Difficult access into central Idaho played a role in the decision to quick-release wolves there. That area consists largely of rugged mountains, and in winter the interior is accessible only by air and to a limited extent by snowmobile....Construction of acclimation pens for the wolves and housing for personnel who would tend the penned wolves would have been difficult and expensive in central Idaho. In Yellowstone, personnel were available, and road access to release sites in high-quality wolf habitat was relatively easy. Using drastically different approaches in the two areas provided an opportunity to learn in a short period which approach held the most potential for population establishment....
....In Yellowstone, three family groups would be held for 6-8 weeks in three separate, 0.4 ha acclimation pens spaced at least 8 km apart. Pen sites were chosen within 2 km of an east-west road in the northern portion of the park, where the highest concentration of wolf activity occurred historically and where ungulates are abundant in all seasons....Areas within 1.6 km of the pens would be closed to the public. Every effort would be made to avoid disturbance or habituation to humans while wolves were in captivity....
At the request of the USFWS, the Idaho Department of Fish and Game chose release sites in central Idaho. Two sites, 14 km apart, were chosen based on aerial access, presence of year-round populations of elk and/or deer, and remoteness from human habitation....
We planned to reintroduce about 15 wolves into both Yellowstone National Park and central Idaho each year for 3-5 years. Thus, 45-75 wolves would be released in each area. Wolves from the same general areas in Canada, but not the same packs, would be used for successive releases. The formal objective of the releases was to provide wolves to both areas until we documented at least two breeding pairs had produced at least two young each for two consecutive years....
Monitoring of the Donor Population
We hoped to obtain 15 suitable wolves each from British Columbia and Alberta in 1994, but we were unable to finalize arrangements with British Columbia officials in time. When Alberta wildlife officials offered to supply all 30 wolves for the first year's effort, our attention shifted there....The Alberta site that became our primary capture area was in the west-central part of the province from about Rocky Mountain House and Edson west to within 32 km of Banff and Jasper National Parks. That area had a population of wolves on provincial lands that seemed high enough to avoid significant effects from the removal of 15-30 wolves annually, and it met all our criteria for a donor population.
For a variety of reasons, we decided to radio-collar and monitor several wolves in the Alberta donor population before holding any animals for reintroduction. Court actions in the United States prevented moving wolves there as early as planned. Second, monitoring would provide basic information on the location, size, and composition of local packs, possibly providing an estimate of wolf density. Third, radio-collared wolves would aid in finding packs and expediting captures when legal clearance was received.
....Alberta Environmental Protection personnel helped establish contact and rapport with over a dozen private trappers who routinely capture wolves in the area and sell their fur.
....In recognition of the importance of trapper cooperation and assistance to reintroduction program success, the USFWS agreed to pay trappers (1) $1440 (U.S.) for each healthy wolf they captured, radio-collared, and returned to the wild, if they would use specialized neck snares, check them daily, and suspend wolf trapping in the area once two wolves were radio-collared; (2) $360 for each additional wolf they captured for actual transport and reintroduction; and (3) $215 for each wolf that reintroduction personnel darted from their registered traplines.
Trappers began setting neck snares for wolves on 1 November 1994. Snares were equipped with stops to prevent excessive loop constriction and avoid strangulation. By 5 December, 13 wolves had been radio-collared at eight locations. While radio-collaring was proceeding in Canada, the final nonessential experimental population rules were published in the Federal Register on 22 November, thus completing all regulatory-procedural processes.
But opponents to the reintroduction had not conceded. On 25 November 1994...the American Farm Bureau Federation and its Montana, Idaho, and Wyoming state chapters requested the federal court to stop any reintroduction of wolves by the USFWS. They alleged that the USFWS violated the law by not adequately analyzing the effects of reintroducing wolves and that their members would suffer irreparable damage to their livestock and private property if the project continued....The court heard legal arguments in Cheyenne, Wyoming on 21-23 December, and on 3 January 1995 issued an order denying any further delays in the program. The capture-hold-transport part of the operation was implemented later that week, about a month behind schedule.
By 3 January the trappers and biologists had placed radio collars on 17 wolves. Another wolf had been net-gunned from a helicopter. Two of the radio-collared wolves had died in the wild from causes unrelated to the program, leaving 16 collared wolves from 13 packs in the donor population when intensive capture work began in early January. Trappers continued to attempt to snare wolves to supplement the helicopter darting. Altogether, 18 Canadian trappers were paid $34,500 for their services, most of which was for radio-collaring wolves. Based on the telemetry data obtained, Alberta biologists conservatively estimated 105-140 wolves in the 7,060 km2 donor area around Hinton, Alberta....
Capturing, Holding, and Transporting Wolves
....A Canadian helicopter company experienced in wildlife capture was contracted to conduct the aerial darting operation; their crew included two helicopters and pilots and one fixed-wing aircraft and pilot. The services of two biologists highly skilled in immobilizing wolves from aircraft were donated to the project by the Alaska Department of Fish and Game. In total, about 30 Americans and Canadians were involved, and about 15 people were on site at any given time during the capture operation....Other biologists in Idaho and Yellowstone prepared for the arrival of wolves.
At Switzer Provincial Park, Alberta, animal handling facilities were assembled in a heated garage to receive captured wolves and conduct all processing. A veterinary field laboratory was established in an adjoining trailer house to centrifuge blood and to package, label, inventory, and store samples. Twenty-three kenenels were constructed outdoors 150 m away from these facilities...in a locked fenced compound. The 4m x 2m x 2m kennels, made of reinforced 9-gauge chain link fence, held the wolves after initial processing and until their destination (Yellowstone or Idaho) was determined and shipment occurred.
....Wolves were immobilized using a Palmer Cap-Chur gun...and 3 cc darts containing tiletamine hydrochloride and zolazepam hydrochloride. Darts were preloaded with 500 mg Telazol mixed with 2.0 cc sterile water and 0.5 cc propylene glycol to prevent freezing of the drug mixture. The relatively small variations in body weight of the wolves made it possible to use uniform drug doses in the darts. Wolves were successfully darted from distances of 3-30m (average about 10m). Weather was favorable for flying during January, but the snow pack was too shallow and hard for easy darting (deep soft snow reduces wolf mobility and maneuverability). That, combined with heavy tree cover over most of the area, made locating and darting wolves challenging. Despite these difficulties, the efficacy of aerial crews improved rapidly as darters and pilots gained experience in working together. In 11 days they successfully darted 28 wolves from 11 packs. Altogether, there were 34 successful captures of 33 wolves (one was released and darted again) during January, including the five snared by trappers....One wolf died when a dart penetrated its body cavity....
After each successful immobilization, a helicopter landed for retrieval of the animal and then ferried it back either to lake ice within 400m of the Switzer Park lab or to some pre-arranged road site where a pickup truck was waiting to transport it to Switzer Park....At Switzer Park the wolves were given a physical examination, treated for any wounds, weighed, and examined for age and breeding condition. Females that had produced pup the previous year were identified based on nipple measurements and were assumed to be alpha females....Identification of the alpha males proved difficult and was surmised based on behavior at the time of darting, estimated age, body size, and testicular size.
Wolves were implanted with a passive integrated transponder...measuring 2.2mm x 11.5mm for permanent identification, as used in the red wolf reintroduction program. They were also fitted with a temporary ear tag for short-term visual identification until the destination of each individual was decided. Blood samples were taken for hematology, serum chemistry, and...serologic tests....Wolves were vaccinated for rabies, canine distemper, parvovirus, hepatitis, leptospirosis, and parainfluenza....They were also dusted with pyrethrin for external parasites and given penicillin....
Wolves were in kennels at Switzer Provincial Park for 1-10 days. This was the first effort known to us that required holding wild-caught wolves for several days, and we did not know how the wolves would respond. Darted wolves seemed to take longer to become calm than snared wolves, perhaps due to the trauma associated with that type of capture. During the first 24-48 hours of captivity several wolves tested the kennel material. Early in the operation, an aluminum transport box was placed inside each kennel for the wolf to use for seclusion, but was removed when some wolves began biting them, injuring their mouths and teeth. We replaced the boxes with bedding of loose straw and bales of straw stacked to create a cavity where wolves could find seclusion. Covering the sides and tops of the kennel with tarpaulins created a visual barrier that appeared to further reduce stress. Noise was minimized near the kennels.  These modifications helped calm the wolves in captivity. Kenneled wolves were fed portions of elk, deer, and moose that had been killed by automobiles and trains and were provided with fresh water daily. Consumption was highly variable between wolves....When observed, they typically were reclining quietly among straw bales in the end of the kennel opposite the door.
We determined if and how each captured wolf would be used in the reintroduction based on its age, sex, breeding condition, probable relatedness to packmates already captured, and the likelihood of capturing additional members of its pack. On the morning of shipping, wolves were anesthetized with Telazol via a syringe pole and were returned to the heated garage. Temporary identifying eartags were replaced with plastic Rototags that had a color and numbering system specific to each reintroduction site. We attached motion-sensitive radio collars to each wolf and gave each transmitter a final check. In addition to providing location data, these collars would indicate when a wolf had died or lost its collar. Each wolf was...given 500 ml Lactated Ringer's solution subcutaneously to prevent dehydration....The time from removal from kennels to loading into transport containers was 2-4 hours. Each wolf was provided a health certificate signed by one of the attending Canadian veterinarians to satisfy U.S. Department of Agriculture requirements. Personnel from Alberta Environmental Protection (Natural Resources Service) drew up research and collection permits and Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITIES) permits that were vital for the international transport of the wolves.
We placed each wolf in an aluminum transport box 1.22m long x 0.66m wide x 0.91m high, loaded them onto an 8-m commercial moving truck, and drove them for 20 minutes to an airport for loading onto a U.S. Forest Service Sherpa twin-engine aircraft capable of holding 18 boxes. Veterinarians accompanied the wolves on the 3-4 hour flight and stayed with them until they were released into the wild or into acclimation pens. Most wolves traveled quietly, although the anesthesia probably wore off before they were airborne....We assumed the wolves were stressed, but there was no indication that any were in shock....Two shipments totaling 29 wolves were made on 11 and 19 January....The sex ratio of the wolves shipped to Idaho was 7 males to 8 females, and for Yellowstone was 9 males to 5 females. Ages of wolves bound for Yellowstone were judged to be 8 adults, 5 subadults and 1 known pup, whereas those taken to Idaho were 9 adults and 6 subadults....Color phases of the wolves were 13 blacks, 15 gray and one considered by local trappers to be the rare "blue" (silver) color phase. Dekker (1986) reported observing 70 black, 59 gray, and 3 white wolves in nearby Jasper National Park from 1965 to 1984 and stated that the percentage of black-phase wolves there was the highest reported. Introduced wolves were from nine different Canadian packs. The Idaho group included members of seven packs and the Yellowstone group four packs; in two instances members of a pack were sent to different areas.
Four captured wolves not used in the reintroduction were released wearing radio collars near their original capture sites on 19 and 20 January. When the capture operation was completed, 12 radio-collared wolves in 10 packs remained in the donor population for continuing monitoring. Alberta began monitoring nine wolves in February 1995. Two radio-collared wolves, both subadults, were subsequently killed in March and April, apparently while dispersing....
Releasing Wolves
While the first shipment of 12 wolves was en route on January 11, the American Farm Bureau filed a legal motion to stop the program, and a Judge of the Federal Appellate court in Denver, Colorado, placed a 48-hour "stay" on the releases to allow himself time to study the motion. The "stay" prevented release of the wolves from the transport boxes. The transport aircraft carrying the wolves landed at Great Falls, Montana, for the scheduled customs check....The eight wolves destined for Yellowstone were picked up at Great Falls and ground-transported to Yellowstone via a horse trailer, arriving early on 12 January amid much fanfare and news media coverage. The first transport boxes were personally carried inside the 0.4-ha acclimation pen by the U.S. Secretary of the Interior and the Director of the USFWS, but the court's stay prevented the wolves' release.
The transport aircraft continued on to Missoula, Montana, on the morning of 12 January with the four wolves destined for central Idaho aboard. The wolves were greeted at the airport by two spiritual leaders of the Nez Perce Tribe, a native American tribe that once occupied much of central Idaho. They held a native prayer ceremony that welcomed back their "brothers," while representatives of nearly a dozen news organizations observed. Because the court's stay also prevented release of these wolves, they and accompanying personnel spent the night of 12 January in the airport hangar while awaiting the judge's decision.
During the court's stay, both the American and Canadian national news networks aired an interview with the U.S. Secretary of the Interior in which he warned that the wolves could die inside their shipping containers because the boxes were not designed for prolonged holding. The possibility of kidney failure and dehydration was a growing concern. Several wolves did take water by chewing on chunks of ice that were placed in the boxes. Animal welfare groups in both the U.S. and Canada threatened to bring charges of animal cruelty against the U.S. government. The USFWS filed an emergency request for reconsideration of the stay, citing the welfare of the wolves. The judge lifted the stay at 6:00 p.m. on 12 January, whereupon the Yellowstone wolves, consisting of six member of a pack (Crystal Creek pen) and an adult female and her pup from another pack (Rose Creek pen) were immediately released into the acclimation pens.
The scheduled airlift of the four Idaho-bound wolves on 13 January was canceled because of bad weather. On that day they were driven from Missoula, Montana, to Salmon, Idaho, where they were held in a U.S. Forest Service garage....With no weather improvement anticipated, plans were developed for release at an alternative site that was accessible by road. On 14 January, after being blessed by members of the Shoshone/Bannock Tribe of southern Idaho, the wolves were driven 96 km to a steep and rugged remote location (Corn Creek) at the edge of the Selway-River of No Return Wilderness that was 77 km northeast of the preselected release points....The wolves appeared in good physical condition as they ran from their opened boxes in mid-afternoon, even though they had spent some 90 hours inside them. One wolf was known to scavenge from a cougar-killed deer carcass that was less than 2 km from the release site, and likely found the deer within an hour of being freed.
The second batch of wolves, 11 for Idaho and 6 for Yellowstone, was shipped on 19 January with less publicity and without legal challenge. Every aspect of the second shipment proceeded more smoothly than the first. After arrival in the U.S., the Idaho wolves were immobilized, removed from their transport boxes, flown by helicopter from Missoula to Hamilton, Montana, and released in central Idaho at the Indian Creek and Thomas Creek sites in the Frank Church River of No Return Wilderness on 20 January. This time, Idaho-bound wolves spent only 20 hours in transport containers. The second group of Yellowstone wolves was flown as far as Bozeman, Montana. This shipment consisted of a large adult male that was placed with an adult female and her pup from a different pack (Rose Creek pen) and a group of 5 (3 males, 2 females) from another pack that was placed in the third Yellowstone pen (Soda Butte pen).
The 14 penned wolves in Yellowstone adapted well to confinement in the 0.4-ha pens. They were fed portions of road-killed elk, bison, deer, and moose at a rate of 6.5 kg/wolf/day. The Crystal Creek wolves were observed from a blind intermittently. No serious aggression was observed among wolves in any of the pens, even though their period of confinement included the time of year when intra-pack aggression is highest.
The adult wolves in the Crystal Creek pen engaged in courtship behavior, and there was evidence of breeding in the other two pens, but no copulation was observed. We later learned that breeding and conception had occurred in the Rose Creek and Soda Butte pens. We were uncertain whether the Crystal Creek group and the Soda Butte group included the pair-bonded alpha male and female from their respective packs. Each group included a female that had produced pups in the past and/or was in a proestrus state when captured and a male that we thought had a high probability of being the alpha male. Previously pair-bonded wolves definitely were not used in the Rose Creek group that we formed through pairing adult wolves from different Canadian packs.
We had planned a 42-56 day acclimation period for Yellowstone wolves to reduce homing tendencies, but extended it to 62-70 days. An even longer confinement might have further increased the likelihood of the wolves remaining together and not traveling widely, but a release well before whelping time (third week of April) and prior to grizzly bears emerging from dens seemed advisable.
Early Results
Virtually all monitoring of the Idaho wolves required aerial telemetry because of the rugged terrain and the wide-ranging movements characteristic of quick-released wolves....Not every wolf was found on every flight because of poor flying weather during spring and extensive movements by some wolves. Most wolves generally traveled a short distance from their release site and remained relatively sedentary for 1-3 weeks before undertaking more extensive movements. The same behavior was noted in previous translocations and reintroductions of wolves. The extent of movements during the following few weeks was highly variable, ranging from remaining near the release site to moving dozens of kilometers away and traversing large areas of Idaho and parts of Montana in a zigzag fashion, sometimes revisiting previous locations.
Female wolf B-13 quickly moved 88 km east of her release site only 9 days after release and was illegally shot at a ranch 40 km south of Salmon, Idaho, as she was feeding from the carcass of a newborn calf. Investigation by the USFWS Forensic Laboratory revealed that the calf had died of nonpredatory causes. Wolf B-3 has not been located since March 8 when she was in southwestern Montana about 140 km northeast of her release site. The wolf most likely moved out of tracking range or was illegally killed and the radio-collar destroyed.
Many translocated wolves in other studies moved toward their area of origin. The initial direction of most Idaho-released wolves was generally northward, as expected, but was east of a homeward direction....[T]he relatively short movements of most wolves kept them well within the recovery zone....The rugged terrain and deep snow may have inhibited travel, although quick-released wolves are known to be capable of traversing extremely rugged mountains. One wolf, B-10, traveled great distances in short periods of time and traversed steep mountain ranges in doing so, but she was not known to travel more than 150 km from her release site (straightline distance).
On 25 June, 13 of the 15 Idaho-released wolves were still within the experimental population zone delineated for central Idaho, having survived in the wild for 156-162 days....Approximate distances from release sites ranged from 30 to 220 km....By the end of June, some Idaho wolves had ranged widely throughout central Idaho and southwestern Montana. The movements of female B-10 were the most extensive, with 800 km (minimum) documented over 14 radio locations in 5 months. Wolf B-2 exhibited the least documented movement of all released wolves, a total of only 200 km (minimum) over 17 radio locations in generally the same period. To our knowledge, only wolf B-10 was observed by the public (except for B-13, which was shot)....
Although pair formation by the wolves in Idaho was not expected during the first several weeks or months after release, two male-female pairs had formed by 25 June. Female B-6 and male B-8 paired within 16 days of release. After two months together the pair separated but reunited in late June in Bear Valley in south-central Idaho about 40 km southwest of their release site....Subadult female B-16 and adult male B-9 had been together since 5 April in the Chamberlain Basin area, some 80 km north of their release sites. Another two wolves, female B-4 and male B-14 were found together on two dates in March, but then separated. In late July a third pair, male B-5 and female B-10, formed near the Idaho-Montana border. By the end of September the three male-female pairs remained together and appeared to have localized their movement. Members of the pairs were from different packs, as is typical in the natural pair-formation process that leads to new packs. Each pair that formed represented a potential breeding unit for the 1996 breeding season.
The Yellowstone wolves were released about 3 months later than originally planned due to the legal impediments. Their confinement totaled 64-79 days and extended to late March, well beyond the February breeding season, by which time we wanted them freed. Two of the three groups nonetheless bred in the acclimation pens. Gates to pens containing the three Yellowstone packs (Crystal Creek, Rose Creek, Soda Butte) were opened on 21, 22, and 27 March, respectively, with food left outside the pens....Most wolves showed an unexpected reluctance to exit pens and remained in them for 1-10 days. Packmates did not all leave pens at the same time....
Thirty-six telemetry flights were completed from late March through 25 June 1995 to locate wolves released into Yellowstone National Park. For the first 2 weeks after release, most wolves restricted their movements to areas near their acclimation pens, and groups of wolves generally remained together. Wolf R-7 separated from her mother and R-10 by 3 April and traveled alone, with the most restricted movements of any Yellowstone wolf, about 390 km2. During the third week all Yellowstone groups undertook exploratory moves with a strong northeastward tendency....These moves brought the groups well outside the park to the edge of U.S. Forest Service land and near private lands and livestock. All but the Rose Creek pair returned to the general vicinity of their acclimation pens within a few days. Perhaps a similar return by the Rose Creek pair was prevented solely by the illegal and unprovoked fatal shooting of R-10 about 10 km south of Red Lodge, Montana, at the edge of U.S. Forest Service land on 24 April. His mate, R-9, gave birth to eight pups at an aboveground site (pit den) in that area on or about 26 April and thus was forced to provide for her pups alone in an environment that placed her in danger from humans. After providing ungulate carcasses for the female for three weeks, we trapped her and transported her and her pups (four males and four females) back to the Rose Creek acclimation pen (80 km) on 18 May, where they were held until 11 October 1995. Their release brought the number of free-ranging wolves in the Yellowstone recovery area to 22. On release, the Rose Creek group was immediately joined by male R-8 from the Crystal Creek pack, who became the new mate of R-9.
....By 25 June, 13 of the 14 wolves released into the Yellowstone area were alive, and 12 individuals (3 groups, 2 solitary wolves) were being tracked in the wild; all were well within the experimental population zone delineated in the final rule for wolf reintroduction to the Yellowstone ecosystem. Approximate distances from release sites on 25 June ranged from 3 to 39 km....The wolves appeared to have no difficulty killing prey in their new environment. The Soda Butte pack killed an elk calf about 1 km from their pen on their first excursion away from the immediate vicinity of the pen and within a few hours of exiting it. The diet of the wolves, as indicated by observation of their kills from the air and snow tracking, consisted almost exclusively of elk.
....The Soda Butte pack established residency in the northeastern corner of Yellowstone National Park and the southwestern corner of the Custer National Forest. This pack made extensive use of drainages that included the site of the acclimation pen. The Crystal Creek pack established a home range in the Lamar Valley region of the park and sometimes traveled near or past their acclimation pen. Each pack ranged over about 650 km2. The location of the Crystal Creek pack near a park highway passing through a wide treeless valley allowed almost daily observation of them from 13 May to 6 July, by which time about 4000 park visitors had observed the wolves.
....Twenty-three years elasped between listing of the wolf as an endangered species and its reintroduction to Yellowstone and central Idaho. The inherent interest in wolves, the strong and conflicting attitudes about them, and their symbolic nature, when added to the current acrimony about how public-owned lands in the American West should be used, created difficulty every step of the way. Reintroducing wolves was far more than just a biological issue. This program has involved more scientific inquiry, media coverage, public attention, and controversy than almost any other North American natural resources issue. Certainly, the public involvement process was one of the most exhaustive for a natural resource issue. Even after a successful first year of reintroductions, with no observable adverse effects to anyone, and positive effects for Yellowstone visitors and local businesses, the reintroduction program remains controversial, and some elected officials want to stop it....
....Much was learned in the first year of the project about how to conduct a gray wolf reintroduction and about what to expect of the reintroduced wolves. We now know that it is possible to capture, transport, hold, and release wild wolves 1,000 km from their capture sites and that wolves can survive these experiences and function as packs or single wolves upon release in unfamiliar habitat. The fact that two of three slow-released packs bred in acclimation pens showed that our efforts to schedule release prior to the breeding season were unnecessary. The formation of three pairs (the first step toward pack formation) by Idaho-released wolves during their first few months of freedom were significant and encouraging events. Pair-bonding occurred even earlier than expected, proving that wolves have the ability and the inclination to seek out mates in such circumstances. One disadvantage of the quick-release approach in Idaho is that the first reproduction will be longer in coming than with slow-released Yellowstone wolves. Nonetheless, both the slow- and quick-release techniques produced satisfactory outcomes, based on these early findings....The fact that during the first 5 months no wolves killed livestock and that none were known to travel outside the experimental population areas intended for them was contrary to the predictions of program opponents and favorable for continued public approval of the program.
....Wolves released in Idaho and Yellowstone appeared to have some sense of the direction toward home, although many initially moved northeastward rather than northwestward. Possibly the lack of reinforcement from failure to encounter familiar sights, sounds, or smells led to the abandonment of northward movement and, in several instances, led to return to the release area....Quick-released Idaho wolves had moved, on average, almost four times farther than the Yellowstone wolves, but due to the size of the central Idaho release area, they were still within remote habitat where opportunities for conflicts with humans were few. The opportunity for wolf-human encounters will increase during the autumn big-game hunting seasons, and some additional mortality then would not be surprising. The death of one Idaho wolf and one Yellowstone wolf were unfortunate but fewer than expected. Clearly, wolves are resilient enough to survive the ordeal of reintroduction and resume their natural predatory role and social lifestyle in new environments.
....The reintroduction design calls for release of 15 wolves to both Yellowstone and central Idaho for 3-5 years to ensure the establishment of self-sustaining populations in both areas and attain recovery goals for the wolf in the Northern Rockies region....Whether any additional wolves are actually reintroduced could depend on political processes outside our control. Controversy surrounding wolves, wolf restoration, and wolf management will not soon disappear.
Appendix 1: data for 14 wolves captured in Alberta, Canada in January 1995 and released into Yellowstone National Park in March of 1995.
Appendix 2: Data for 15 wolves captured in Alberta, Canada and released into central Idaho, January 1995.
Figure 1: Recovery areas for the wolf in the northern Rocky Mountains of the United States according to the Northern Rocky Mountain Wolf Recovery Plan and experimental population areas where wolves are managed according to nonessential-experimental population rules.
Figure 2: General area of capture and areas of release of wolves reintroduced to central Idaho and Yellowstone National Park in January 1995.
Figure 3: Locations of wolves released into central Idaho and Yellowstone National park from release through June 1995.
Figure 4: A biologist examining a wolf near Hinton, Alberta, after immobilizing the animal by darting from a helicopter.
Figure 5: USFWS biologist Alice Whitelaw removes an immobilized wolf from a kennel in order for it to be prepared for shipping to the United States.
Figure 6: U.S. Secretary of the Interior, Bruce Babbitt, and USFWS Director, the late Mollie Beattie, assist in carrying first wolf to Crystal Creek acclimation pen in Yellowstone National Park.
Figure 7: Wolf exiting transport container at its release site in central Idaho.
Figure 8: Wolf in pen during its acclimation period in Yellowstone National Park.
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