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USDA FOREST SERVICE RESEARCH PAPER NC-52 1971

Ecological Studies of the TIMBER WOLF in Northeastern Minnesota

NORTH CENTRAL FOREST EXPERIMENT STATION FOREST SERVICE U. S. DEPARTMENT OF AGRICULTURE

FOREWORD

The largest population of timber wolves remaining in the United States (excluding Alaska) lives in northern Minnesota. Many of these wolves inhabit the Superior National Forest, so protecting the habitat of this endangered species is largely a Forest Service responsibility.

As the "Age of Ecology" broadens into the 1970's, wolves and wolf habitat will become a subject of concerted research. Forest land managers will have to know more about how the timber wolf fits into a forest system. Building on nearly 50 years of research in northern forests, we at the North Central Station intend to expand our studies of wildlife habitat. We are happy to publish the enclosed papers as one step in this direction.

D. B. King, Director

North Central Forest Experiment Station D. B. King, Director Forest Service--U.S. Department of Agriculture Folwell Avenue St. Paul, Minnesota 55101

ECOLOGICAL STUDIES OF THE TIMBER WOLF IN NORTHEASTERN MINNESOTA

L. David Mech and L. D. Frenzel, Jr. (Editors)

CONTENTS

Movements, Behavior, and Ecology of Timber Wolves in Northeastern Minnesota L. David Mech, L. D. Frenzel, Jr., Robert R. Ream, and John W. Winship 1

An Analysis of the Age, Sex, and Condition of Deer Killed by Wolves in Northeastern Minnesota L. David Mech and L. D. Frenzel, Jr. 35

The Effect of Snow Conditions on the Vulnerability of White-Tailed Deer to Wolf Predation L. David Mech, L. D. Frenzel, Jr., and P. D. Karns 51

The Possible Occurrence of the Great Plains Wolf in Northeastern Minnesota L. David Mech and L. D. Frenzel, Jr. 60

THE AUTHORS

Dr. Mech, formerly with the Department of Biology, Macalester College, St. Paul, Minnesota, is now employed by the U.S. Bureau of Sport Fisheries and Wildlife, Twin Cities, Minnesota.

Dr. Frenzel, formerly with the Department of Biology, Macalester College, St. Paul, Minnesota, is now employed by the Department of Entomology, Fisheries, and Wildlife, University of Minnesota, St. Paul, Minnesota.

Dr. Ream, formerly with the North Central Forest Experiment Station (maintained in cooperation with the University of Minnesota), Forest Service, U.S. Department of Agriculture, is now employed by the School of Forestry, University of Montana, Missoula, Montana.

Mr. Winship is with the U.S. Bureau of Sport Fisheries and Wildlife, Twin Cities, Minnesota.

Mr. Karns is with the Minnesota Department of Conservation, Forest Lake, Minnesota.

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402

MOVEMENTS, BEHAVIOR, AND ECOLOGY OF TIMBER WOLVES IN NORTHEASTERN MINNESOTA

L. David Mech, L. D. Frenzel, Jr., Robert R. Ream, and John W. Winship

The largest population of wolves (Canis lupus) remaining today in the continental United States outside of Alaska is in northern Minnesota. As of mid-1970 this population was not legally protected, and the species, which once ranged over almost all of North America, is now considered by the U.S. Department of the Interior to be in danger of extinction in the contiguous 48 States. Until the present research, the only field studies of Minnesota wolves were those of Olson (1938 a, b) and Stenlund (1955). Those investigations provided much useful general information about Minnesota wolves and gave the present authors an excellent background with which to begin more detailed investigations.

This paper reports on the basic aspects of a series of studies that began in 1964, and concentrates primarily on wolf movements and activity, social behavior, hunting behavior, and population organization. Most of the data were collected during January, February, and March 1967; February, November, and December 1968; and January through August 1969. A total of 192 days was spent in the field.

According to a distribution map of wolf subspecies (Goldman 1944), the race of wolves in our study area is Canis lupus lycaon. However, evidence presented by Mech and Frenzel (see page 60) suggests that there may be strong influence by C. l. nubilus, a more western race of wolf formerly thought to be extinct (Goldman 1944).