An Experimental Translocation of the Eastern Timber Wolf Part 1

An Experimental Translocation of the Eastern Timber Wolf.

by Thomas F. Weise and William L. Robinson and Richard A. Hook and L. David Mech.

FOREWORD

The Fish and Wildlife Service is proud to present this bulletin describing an experimental attempt to re-establish an endangered species in part of its native range. Two States, a Federal agency, a university, and two private conservation groups pooled their resources to make the project possible. This effort exemplifies the type of cooperation the Department of the Interior believes is imperative in beginning the gigantic task of trying to save and restore the threatened and endangered animals in this country today.

Our pride is bittersweet, however. The experiment was a complete success in providing the information sought: What might happen when a pack of wolves is transplanted to a new area where the native population has been all but exterminated by Man? It was the answer to this question that was disappointing. Nevertheless, experiments are for learning, no matter what the answers may be. We are convinced that the answers provided by this project will ultimately be most helpful in future attempts to restore endangered animals to parts of their native ranges where they can begin again on the road to recovery.

[Ill.u.s.tration: Lynn A. Greenwalt]

DIRECTOR

U. S. Fish and Wildlife Service

INTRODUCTION

The eastern timber wolf (_Canis lupus lycaon_) originally occurred throughout the eastern United States and Canada but is now extinct in most of the United States. The only substantial population left inhabits northern Minnesota (Fig. 1). The estimated wolf population in the Superior National Forest of northeastern Minnesota in winter 1972-73 was about 390 (Mech 1973), and a tentative population estimate for the entire state is 500 to 1,000 (Mech and Rausch 1975). A well known population of about 15 to 30 wolves is also found in Isle Royale National Park, Lake Superior, Michigan (Mech 1966; Wolfe and Allen 1973; Peterson 1974).

[Ill.u.s.tration: _Fig. 1.--Original and present range of the Eastern Timber Wolf_]

In the Upper Peninsula of Michigan, Hendrickson et al. (1975) estimated the wolf population in 1973 at 6 to 10 animals, existing in three scattered areas: Iron County, Northern Marquette County, and Chippewa and Mackinac Counties (Fig. 2). Lone wolves made up 90 per cent of verified wolf observations there in recent years, and no more than two animals have been found together in at least the past 13 years.

Hendrickson et al. (1975) postulated that the current low wolf population is maintained through possible sporadic breeding and immigration from Ontario and Minnesota (via Wisconsin), but is suppressed by illegal shooting and losses incidental to coyote (_Canis latrans_) bounty trapping.

The eastern timber wolf was cla.s.sed as an endangered species in the conterminous United States in 1967 under the Endangered Species Act of 1966. There then followed widespread national and international concern and support for preserving natural wolf populations. Substantial scientific and ethical arguments exist for preventing the extinction of a species or subspecies of any plant or animal. In addition, the presence of the wolf adds immeasurably to a wilderness experience; its esthetic value is incalculable.

Thus in 1970, D. W. Dougla.s.s, Chief of the Wildlife Division, Michigan Department of Natural Resources, suggested that restoration of a viable population of wolves in Michigan would be desirable, especially if such efforts could be supported by private organizations. In 1973 the Huron Mountain Wildlife Foundation and the National Audubon Society offered financial support, and we undertook this pilot project to obtain information necessary for a full-scale restoration effort.

The objectives of the research project were to determine whether (1) wild wolves could be moved to a new location, (2) such translocated wolves could remain in the new area, (3) they could learn to find and procure enough food in the new area, (4) they could tolerate and survive human activities, and (5) they would breed and help to re-establish a new population in Upper Michigan.

As background we had the results of three previous attempts to transplant wolves to new areas. In 1952, one male and three female zoo wolves were released on Isle Royale (Mech 1966). They were attracted to humans, became nuisances, and had to be disposed of. Two were shot, one was captured and returned to the mainland, and the male escaped; his fate is unknown.

The second transplant effort took place on uninhabited, 36-square-mile (92 km) Coronation Island in southeastern Alaska (Merriam 1964; Mech 1970). In 1960, two male and two female, 19-month-old captive wolves, were released there. They learned to prey on black-tailed deer (_Odocoileus hemionus columbia.n.u.s_), and multiplied to about 11 members by 1964.

In the third case, two male and three female laboratory wolves from Barrow, Alaska were released near Umiat in August 1972, 175 miles (282 km) southeast of Barrow (Henshaw and Stephenson 1974). Eventually, all moved toward centers of human habitation and three were shot within 7 months. A fourth returned to the pens where she was reared, and was recaptured, while the fate of the fifth wolf remains unknown. Three of the five had taken the correct homing direction.

Because results of the earlier attempts at translocating wolves suggested that pen-reared wolves did not fare well in the wild, we decided to use wild wolves that were accustomed to fending for themselves and avoiding people. They would have to be released in the most inaccessible area we could find and encouraged to stay there. To maximize their chances of breeding, we would have to try to obtain animals with already established social ties, that is, members of the same pack. Approval was obtained from the Minnesota Department of Natural Resources to live-trap up to five wolves in Minnesota, and a permit was granted by the Michigan Department of Natural Resources to release up to five in Upper Michigan.

This bulletin describes the results of the experimental translocation.

THE STUDY AREA

The area selected for the release of the translocated wolves was the Huron Mountain area (Fig. 2) in northern Marquette County in the Upper Peninsula of Michigan (47 N Lat.i.tude; 88 W Longitude). This is one of the largest roadless tracts in Michigan, and has one of the lowest year-around densities of resident humans. Much of the area is owned by the Huron Mountain Club, on which accessibility is restricted.

The Upper Peninsula is 16,491 square miles (42,693 km) in area, bounded by Lake Superior to the north, and by Lakes Huron and Michigan to the east and south. The Wisconsin border along the western portion of the Upper Peninsula forms no distinctive ecological boundary. The Upper Peninsula is in the Canadian biotic province (Dice 1952), characterized by a northern hardwoods climax, interspersed with spruce-fir and pine subclimaxes. The northwestern portion of the Upper Peninsula, including Marquette, Baraga, Houghton, Ontonagon, and Iron Counties, contains rugged highlands and rock outcroppings which rise to elevations approaching 2,000 feet (610 m) in several locations.

The human population of the Upper Peninsula is 303,342, with a rural density of about 9.0 persons per square mile or 3.5 persons per square kilometer (Table 1). The population of the Upper Peninsula has remained at about 300,000 for the past 50 years, and the rural human populations of local areas have generally declined or remained stable. During those 50 years, the wolf population has declined from several hundred animals to near extinction, with the population estimated by Hendrickson et al.

(1975) at 6 to 10 remaining wolves. These authors concluded that the bounty on wolves between 1935 and 1960 was largely responsible for the demise of the species in the Upper Peninsula. The bounty was removed in 1960, after only one wolf was taken in 1959. Legal protection was granted by Michigan in 1965. The Endangered Species Act of 1973 added federal protection in 1974.

The white-tailed deer (_Odocoileus virginia.n.u.s_) would be the major prey for wolves in Michigan, and there appear to be sufficient numbers to support wolves. The Michigan Department of Natural Resources pellet count estimates for the spring deer population in the Upper Peninsula in 1973 was 10 21.9% deer per square mile (3.9 21.9% per km). Deer densities of 10 to 15 per square mile (3.9 to 5.8 per km) supported wolf densities of one wolf per 10 square miles (26 km) in Algonquin Provincial Park, Ontario (Pimlott 1967).

The population of deer wintering on the 14 square-mile (36 km) Huron Mountain deer yard in winter 1973-74 was estimated at 73.3 49.5% deer per square mile (28.3 49.5% deer per km) by the pellet count method (Laundre 1975). Thus total wintering population on the Huron Mountain Club, the wolf release area, would be about 1,000 deer.

The utilization of available browse by deer in the Huron Mountain deer yard reached 95% by March 8, 1969 and 92% by March 5, 1970 (Westover 1971). The minimum winter deer loss (actual number found) in 1969 was 40 animals, of which at least 12 had starved, and it was estimated that perhaps up to 33% of the deer starved in the Huron Mountain Yard in 1968-69 (Westover 1971). The Huron Mountain yard continues to be overbrowsed, with high deer mortality expected in severe winters. Many other northern deer yards of the Upper Peninsula are also overbrowsed and are dwindling in area. Thus we expected that numbers of vulnerable deer (Pimlott et al. 1969; Mech and Frenzel 1971) would be available to wolves.

Beavers (_Castor canadensis_) are an important food source for wolves in many areas during summer (Mech 1970), and they are common throughout the Upper Peninsula. The beaver population on the 26 square-mile (67 km) Huron Mountain Club was estimated at 46.9, or about 1.9 beavers per square mile (0.7 per km) (Laundre 1975). Moose (_Alces alces_) are rare on mainland Michigan.

METHODS

The general procedure for this study was to attempt to capture an intact pack of wolves in Minnesota, fit each animal with a radio-collar (Cochran & Lord 1963), release them in northern Michigan, and follow their fate through aerial and ground radio-tracking (Kolenosky and Johnston 1967).

A pack was selected from an area near Ray, Minnesota (Fig. 3), south of International Falls (48 N Lat.i.tude, 93 W Longitude), where wolf hunting and trapping were legal. Two male and two female wolves were captured by professional trapper Robert Himes, under contract for the project, between December 24, 1973 and January 21, 1974 (Table 2). Three of the wolves were trapped (Fig. 4) in No. 4 or 14 steel traps (Mech 1974), and one (No. 13) was live-snared (Nellis 1968). If these animals had not been solicited for this study, they would have been killed and their pelts sold, as part of the trapper's livelihood, before the Endangered Species Act of 1973 took effect.

[Ill.u.s.tration: _Fig. 3.--Capture and release points of the translocated wolves_]

At capture each wolf was immobilized with a combination of phencyclidine hydrochloride (Sernylan) and promazine hydrochloride (Sparine) intramuscularly (Mech 1974), with dosage recommendations from Seal et al. (1970). They were then carried out of the woods (Fig. 5), held in pens in Minnesota, and fed road-killed white-tailed deer, supplemented with beef sc.r.a.ps.

[Ill.u.s.tration: _Fig. 4.--Wolf caught in trap (Photo by Don Breneman)_]

[Ill.u.s.tration: _Fig. 5.--The captured wolves were drugged and carried to an enclosure in Minnesota (USFWS Photo by L. David Mech)_]

There is no certain way of ascertaining that wolves are related or that they belong to the same pack. Thus to maximize chances that members of the same pack would be captured, the trapper set traps where he suspected only one pack ranged. To try to determine whether the individual wolves he caught were socially related, we instructed the trapper to hold the wolves in individual pens until we could observe their introductions to each other. Wolves No. 10 and 11 were placed together on January 23, 1974, and No. 13 and 14 were released into the pen with No. 10 and 11 on February 4.

[Ill.u.s.tration: _Fig. 6.--Before being transported to Michigan, each wolf was weighed (USFWS Photo by Don Reilly)_]

_Table 2. Background information on the translocated wolves_

---------------------------------------------------------------------- Wolf Number 10 11 12 13 ---------------------------------------------------------------------- s.e.x F F M M

Estimated age[9] 1-2 years 6-7 years 2-3 years 2-3 years