Prey of Wolves in the Great Lakes Region

Abstract

Wolves (Canis lupus) were abundant in the Great Lakes region just prior to early European settlement (early to mid-1800s). The subsequent extirpation of wolves and most of their large prey is just one of the many threats humans have posed to the existence of North American wildlife, both by exploitation and by indifference. To fully understand (and learn from) the recent ongoing recovery of wolves in the Great Lakes region (Minnesota, Wisconsin, and Michigan), and the historic declining trend that preceded it, requires consideration of their food or prey, both historically and today. Ungulate prey species are often at the center of the wolf-human conflict, where and when it occurs. What history, recent management, and research have taught us is that it was not wolf predation that diminished the diversity and richness of ungulate species in the Great Lakes region, but rather the human “appetite,” and unfortunately for wolves and their prey, the unprecedented drive to satisfy it. On the other hand, humans have a great capacity for conservation when that is their true intention. But the success of such efforts also relies largely on species-specific biology, in this case, not just of wolves, but of their existing prey as well. Wolves are adaptable, opportunistic predators when it comes to their foraging behavior, but what animal species become their prey has depended largely on the potential prey’s size, abundance, and vulnerability. Consequently, the relative contributions of primary and secondary prey to the diets of Great Lakes wolves, to their individual health and welfare, and long-term population persistence, have changed historically, and today continue to vary seasonally, annually, and across the landscape. This chapter begins with a brief description of the historic trends in distribution and relative abundance of the large ungulates that were likely most important in the multi-prey system of the Great Lakes wolf. Our major focus, however, is the more recent trend of whitetailed deer (Odocoileus virginianus), the wolves’ primary prey in a single ungulate prey system that has persisted throughout the 20 century and during their recent ongoing recovery. We concentrate our discussion on specific aspects of the deer’s ecology that have enabled its populations to thrive despite relatively heavy human exploitation, increasing numbers of wolves, and a concomitant expansion of their range. This discussion is based upon management efforts and an unparalleled amount of data generated from the study of coexisting white-tailed deer and wolves in the Great Lakes region. We devote similar, but more limited attention to moose, which are primary or secondary prey for wolves on Isle Royale and in various portions of northern Minnesota.