The translocated wolves apparently scavenged more in Michigan than in Minnesota, at least shortly after their release. There were no known garbage dumps within their native territory. The dumps in Michigan presumably offered more readily available food during a time when the wolves appeared preoccupied with extensive travel.
Nevertheless, the wolves did kill at least the three deer that we found, and no doubt took several others. Although the sample size is small, the results of our analysis of the condition of the deer are consistent with those from other studies, indicating that wolves prey primarily on debilitated deer (Pimlott et al. 1969, Mech and Frenzel 1971).
All three deer killed by the wolves were seriously malnourished, with 6% or less fat content in the marrow of their femurs, or thigh bones. At less than 25% fat in the marrow, serious malnutrition has developed (Cheatum 1949). (In comparison, the femur fat of 59 doe deer killed by automobiles in the Upper Peninsula in March and April 1974 averaged 46%, according to Dr. L. D. Fay, Michigan Department of Natural Resources.) In addition, one of the animals killed by the wolves had been wounded by a bullet and had a broken leg; all three were does, and were over 4 years of age, a factor that Pimlott et al. (1969) and Mech and Frenzel (1971) have also found important in wolf kills.
An Alternate Approach
Although the time of release for the four wolves in this study was selected in order to maximize chances that they would remain in their new range, possibly a release earlier in winter would be more successful. The failure of the adult female to conceive was probably a result of captivity and handling, although this needs confirmation through additional studies. Nevertheless, an early winter release might be favored by deep snows hindering travel. Furthermore, by breeding season in late February the wolves might already have settled into an area. Then the entire breeding cycle might take place outside captivity and stand a better chance of succeeding.
CONCLUSIONS
Three principal conclusions can be drawn from the results of this experiment: (1) It is possible to transplant a pack of wild wolves into a new range. That new range, however, must be large enough to permit some initial wandering. The animals cannot be expected to establish a home range centered on or even including the point of release. (2) The habitat in Upper Michigan apparently is adequate to support wolves, in terms of food and cover, for the carcasses of the two experimental wolves that could be examined intact had maintained or improved their condition during their 6-to-8-month residence in Michigan. (3) The reason for the failure of the experimental wolves to re-establish themselves was direct mortality by human beings, just as Hendrickson et al. (1975) concluded was the case for the failure of native and immigrant Michigan wolves to re-establish a population. This mortality probably is related to two factors, negative human attitudes toward wolves and accessibility of humans to wolf range.
We are convinced that, ecologically, wolves can be re-established in Upper Michigan. However, a successful program of re-establishment will require the following:
1. A survey of public attitudes in Upper Michigan toward re-establishing wolves,
2. An intensive public relations campaign to promote an understanding of wolf ecology and the benefits of a wolf population,