by Mike Phillips
The rescue of the red wolf from the brink of
extinction
has been one of conservation's success stories. The reintroduced
wild population is increasing annually.
[Ed. - we plan to post the figures on-line soon!]
Red wolves once ranged throughout the southeastern United States before European settlement of that region, but by 1980 was considered extinct in the wild. The demise of the red wolf was due to many factors: manµs persecution of wild canids and the destruction of optimal habitat forced the few remaining red wolves into marginal habitat in Louisiana and Texas where they interbred with coyotes and suffered heavy parasite infestation.
The plight of the red wolf was recognized in the early 1960s. The species was listed as endangered in 1967, and a recovery programme was initiated after passage of the Endangered Species Act of 1973. During the early 1970s the U.S. Fish and Wildlife Service (USFWS) realized that the species' recovery could only be achieved through captive breeding and reintroduction to the wild.
By 1976 a captive breeding programme had been established utilizing 17 red wolves captured in Texas and Louisiana. In 1977 the first pups were born, and by 1985 the captive population numbered 65 individuals held in six zoological facilities.
With the species reasonably secure in captivity, the USFWS initiated a reintroduction project in 1987. Since this represented the first ever attempt to restore a carnivore species which had been declared extinct throughout its former range, the programme generated tremendous public interest in the red wolf. Between September 1987 and April 1991 a further 18 zoological facilities committed themselves to maintaining red wolves, and the annual federal budget for captive breeding increased from about $30,000 to $191,000. By January 1991 there were 159 red wolves in captivity; currently there are at least 220.
In 1984 the red wolf was selected for inclusion in the American Association of Zoological Parks and Aquaria Species Survival Plan (Plan) programme. Inclusion in this programme provided the impetus and expertise needed to intensify management of the species in captivity.
The Plan delineates and schedules actions necessary to ensure genetic stability and reintroduction of the species to the wild. Specifically, the goal of the plan is to maintain 80-85% of the genetic diversity found in the original founder stock for at least 150 years. This goal is equivalent to preserving 90% of the heterozygosity present in the existing captive population. A population viability analysis indicated that to meet the above objective, the USFWS would have to establish a population of 550 red wolves. Furthermore, it was decided that these 550 would be distributed between a captive population of 330 and a free-ranging population of 220 distributed at three or more sites.
In 1987 a reintroduction project was initiated in northeastern North Carolina in the Alligator River National Wildlife Refuge (ARNWR), which covers 60,727 ha, and adjacent Department of Defence land, which covers 18,218 ha (see Fig.1). The reintroduction area consists of marshes, non-riverine swamp forests, pocosins (a common habitat on the coastal plain of southeastern USA, characterized by an understory of evergreen shrubs and an overstory of pond pines) and agricultural fields. The region's climate is characterized by hot summers, mild winters and high humidity. The area is bisected by numerous logging roads, many of which are only seasonally passable with a 4-wheel drive vehicle or on foot. The area supports abundant prey, including white-tailed deer, raccoons and marsh rabbits, but there are no coyotes, feral dogs or livestock present. In addition the area is sparsely settled, and surrounded on three sides by large bodies of water that wolves are unlikely to cross successfully.
The decision to conduct the reintroduction was dependent upon public acceptance of the proposal. The USFWS briefed representatives of environmental organizations in Washington D.C., along with the North Carolina Congressional Delegation, the North Carolina Department of Agriculture, the Governor's office, local officials and local landowners. The U.S. Air Force and Navy were briefed because they conduct training missions on 18,218ha adjacent to the refuge. Numerous personal contacts were made with local citizens, especially hunters and trappers, in preparation for public meetings held during February 1986. At the briefings and meetings considerable effort was made to explain the significance of the decision to consider reintroduced wolves wolves as members of an ·experimental/nonessentialº population.
The experimental/nonessential designation was promulgated under the 1982 amendments to the ESA and provided the USFWS with the opportunity to relax restrictions of the ESA to encourage cooperation from those likely to be affected by the reintroduction. The flexibility of the designation was important in soliciting support for the reintroduction.
The regulations developed for the reintroduction project prohibited taking of red wolves by the public to prevent the loss of livestock or property damage. In instances of depredations, citizens were required to contact USFWS or state conservation officers authorized to initiate control measures. Such control could include lethal means only if attempts to capture the animals concerned failed, or if there was clear danger to human life. No compensation programme to offset depredations was developed because livestock were virtually absent in the area.
Human activities in the refuge included public trapping and hunting, which could accidentally kill a red wolf despite reasonable care by sportsmen. The USFWS proposed that prosecution should not be pursued when the accident was unavoidable, unintentional, did not result from negligent conduct, and was immediately reported to authorized personnel. The regulation also stated that wolves could be taken in defence of human life, although such circumstances were considered extremely unlikely.
Wolves selected for release were taken from the USFWS's certified captive-breeding stock. Age, health, genetics, reproductive history, behaviour, and physical traits representative of the species were considered in the selection process.
Before release, each wolf was acclimated in 255m² pens at the refuge. We employed acclimation in order to prepare the wolves for life in the wild and to attenuate their tendency to travel widely immediately following release. Acclimation periods for adults were purposefully lengthy and averaged 18.7 months (n=42, sd=13.5 months), with the exception of two adults that were acclimated for 2.2 months.
We were naturally worried about the effect that long-term captivity would have on the wolves' ability to survive. Accordingly, during acclimation we minimized human contact, hoping to reduce the wolves' tolerance of humans. We varied the feeding regime to expose the animals to feast or famine, weaned the wolves from dog food and fed them an all-meat diet, and provided the opportunity to hone predatory skills by giving them live prey.
During pre-release health checks we administered a standard series of canine vaccines, vitamin supplements and a parasiticide, determined weights, took blood samples and fitted the wolves with motion-sensitive radio-collars. The first nine adults were also implanted with abdominal transmitters as back-ups to radio-collars. Nine of the first ten adults were also implanted with radioactive tags that allowed us to assign collected scats to individual wolves (Crabtree et al., 1989). All pups were fitted with abdominal transmitters at about 10 weeks of age.
White-tailed deer carcasses were placed at initial release sites with the intent of decreasing the chances of wolves immediately ranging widely in search of food. Supplementary feeding continued for a month or two after release to provide the wolves with the opportunity to learn to forage successfully in unfamiliar terrain. Supplementary food was sometimes provided for wolves being re-released.
Between 14th September 1987 and 31st December 1995, 63 captive-born red wolves were involved in 76 releases: 32 adults (16.16) and one female yearling in 45 releases, and 31 (16,15) pups in 31 releases. We released each wolf once, except for three adults that we released three times, and six adults that were released twice. We defined a release as an initial release or a re-release of a wolf in a different area or with a different social group, and a successful release as one that resulted in the released wolf breeding and producing pups in the wild.
We conducted releases every year from 1987 onwards. Most releases (71%) were carried out between August and October when pups were 4-6 months of age, and usually involved families or adult pairs. Unforeseen circumstances resulted in most wolves being re-released on numerous occasions at various times of the year.
Animals were released either as members of 14 adult pairs, 8 families, one sibling group, one adult/yearling pair, and one adult/pup pair. We defined adults as animals > 24 months old, and pups < 12 months of age.The adults released ranged in age from 2.25-7.33 years.
Forty-four of the 45 releases of adults and the yearling were conducted early enough in the experiment to be potentially successful by December 1994. We excluded the release of 316F during September 1989 because she disappeared during December of that year; her radio-collar probably malfunctioned.
Of these 44 releases, only 12 (27%) were in fact successful. Wolves involved in the successful releases persisted in the wild for an average of 22.1 months (n=12, sd=17.6 months).
Thirty-one captive-born pups were involved in 31 releases. We cannot comment on the outcome of four of these releases because the pups disappeared before experiencing a breeding season in the wild. Of the 27 remaining, 11% (n=3) were successful. These three pups were still free-ranging and consorting with their mates as of 31st December 1994; they had persisted in the wild for an average of 61.6. months (sd=4.4 months).
During the restoration programme a minimum of 22 litters containing 66 pups (30 males, 27 females, and 9 of unknown sex) were conceived and born in the wild. Litters were produced in the wild every year except for 1989 when there were no pairs together during the breeding season. The average litter contained at least three pups although we documented litters that contained just one pup and litters that contained as many as five pups.
The 11 captive-born adults involved in the successful releases contributed to nine litters that contained 25 pups, or 38% of the total number of pups that were conceived and born in the wild, whereas the three captive-born pups involved in successful releases contributed to seven litters that contained at least 24 pups (36% of the total). Eleven wild-born wolves themselves bred in the wild and contributed to 12 litters containing a minimum of 36 pups (54% of the total number born).
Of the 66 pups, as of 31st December 1994, 54% (n=36) were free-ranging, 23% (n=15) had unknown fates, 15% (n=10) had died, and 8% (n=5) had been returned to captivity. The oldest wild-born free-ranging red wolf was 79.9 months (344F). Wild-born red wolves that died persisted for an average of 13.5 months (sd=13.6 months).
On average the 51 pups that were conceived and born in the wild and whose fates were known to us persisted for 21.8 months (sd=17.9 months), whereas the 27 captive-born pups we released whose fates were known to us persisted for only an average of 13.4 months (sd=18.7 months). The 44 captive-born adults and the yearling whose fates were know to us persisted for only an average of 8.0 months (sd=12.9 months). Wild-born pups persisted for significantly longer periods than did either adults or pups we released (c²=12.58, p<0.001).
Of the 135 red wolves involved in the restoration effort between September 1987 and the end of December 1994, 51 (38%) individuals died whilst free-ranging. A number of factors caused the death of a few red wolves: ingestion of poison, a trapping accident and a handling accident each led to the death of a wolf, three wolves died of unknown causes, and four were shot by individuals who were not sympathetic to the plight of the species.
Of the remaining 41 deaths, 36% (n=15) were accidental and caused by vehicles and 64% (n=26) were caused by a variety of non-human factors including intraspecific aggression, drowning, mange, malnutrition and parasites, and natural causes.
The size of home ranges for reintroduced wolves that established themselves in the wild and wild-born wolves varied according to habitat. In forested areas consisting of pine/hardwood swamps in various stages of succession, the home range of one pack that included 11 different wolves was about 100km². In agricultural areas consisting of planted fields interspersed among early to mid successional fallow fields and pine/hardwood stands, the home ranges of eight lone wolves and four packs involving 30 different wolves measured about 50km². The relative abundance of prey in agricultural areas may account for the differences in home range size exhibited by red wolves.
Scat analysis indicated that white-tailed deer, raccoon and marsh rabbits were primary year-round food items and accounted for 88.7% of the biomass consumed by wolves. Although some of the deer were probably eaten as carrion, we documented wolf predation of apparently healthy deer.
We knew from the outset that we would have to intensively manage the wolves in order to ensure the establishment of the population and adequate resolution of wolf/human conflicts. Furthermore we realized that while the restoration effort was not a research initiative it did offer us an unparalleled opportunity to acquire new knowledge about red wolves and endangered species restoration. However, because the wolves are so wide-ranging and secretive, the only way to ensure our success was to embrace radio-tracking as our primary field method. Accordingly, capturing wolves for telemetric purposes became our primary field activity. Once wolves were captured we could attach or replace radio-collars and if necessary implement management actions that had been specifically crafted for that particular wolf.
We captured 45 of 63 released wolves (71%) 110 times in total, and 59 of the 71 wild-born wolves (83%) 125 times. We accomplished 195 of these captures (83%) using leghold traps. Additionally, we modified acclimation pens to act as traps for 27 captures (11%) of 12 captive-born wolves and one wild born wolf. We accomplished the remaining 13 captures using a variety of techniques including dart guns, box traps and nets.
Aerial telemetry was our primary method of maintaining contact with radio-collared wolves. From September 1987 to the end of December 1994 we logged 1,345 hours in fixed-wing aircraft during 906 telemetry flights. During these flights we recorded over 10,000 wolf locations.
Capturing animals and monitoring them telemetrically allowed us to determine the outcome of 71 of the 76 releases (93%) of captive-born red wolves and the fates of 56 of the 71 wild-born wolves (79%). These figures vividly illustrate that red wolves can be restored to northeastern North Carolina in a controlled manner.
The red wolf restoration programme progressed considerably during the seven years from 1987 to 1994. As of 31st December 1994 a minimum of 42 red wolves were free-ranging, including 36 wild-born animals. Most of these animals (76%) inhabited private land. Since 1988 we have integrated about 60,000 acres of private land into the restoration area at a cost of $3,951 per year for 5 years. Private land increased the size of the restoration area by 25%. Red wolves now have access to 320,000 acres of forest, swamps, marshes and agricultural fields in northeastern North Carolina. Within the next few months we hope to add another 130,000 acres of private property. Parties involved include Weyerhaeuser, Georgia-Pacific and private citizens.
During February 1995 we expect about eight pairs to breed in the wild, resulting in the production of about 25-30 pups that mature to an age of self-sufficiency. Thus by December 1995 the red wolf population should number about 60-70 animals. We expect that over 100 wolves will come to inhabit northeastern North Carolina by the year 2000.
We feel that by every measure the reintroduction was successful and generated benefits that extended beyond the immediate preservation of red wolves, to positively affect local citizens and communities, larger conservation efforts and other imperilled species. During the reintroduction two important points surfaced:
* Mike Phillips was the coordinator of field projects for the red wolf recovery programme for several years, until he recently moved to Yellowstone to direct the programme to reintroduce the grey wolf there. His interests include management of canid populations and endangered species restoration.
© 1995 International Union for the Conservation of Nature and Natural Resources
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