Ecological Studies of Wolves on Isle Royale - Annual Report 1980-1981 (Covering the twenty-third year of research)
Peterson RO, Stephens PW, Shelton PC. 1981. Ecological Studies of Wolves on Isle Royale - Annual Report 1980-1981 (Covering the twenty-third year of research). Department of Biological Sciences, Michigan Technological University. Houghton, MI
This report summarizes the results of the 23rd year of field studies on Isle Royale including summer and winter moose studies. We primarily describe wolf movements and population status during the winter studies. The 1981 wolf population dropped from 50 to 30 individuals, the most dramatic wolf decline in the 23 year history of this research project which is attributed to a reduced food supply. Current effort in following the moose population dynamics is directed at a determination of moose density and population composition. Results of summer and fall moose population surveys are reported. The winter aerial census of moose revealed a population of 481 animals. Other species observed during the winter study period were beaver, otter, and fox. In October 1980, Shelton surveyed beaver colonies by air and ground and attempted to live-trap three colonies. The decline in numbers of colonies with food piles was essentially linear from 1974 through 1980. In 1980, there were 39 sites with fresh cutting or fresh mud on the house and 122 total sites with signs of activity.
- Type
- Published Report
- Authors
- Peterson, Rolf; Stephens, Philip; Shelton, Philip
- Date of Issue
- 1981-04-30
- Publisher
- Department of Biological Sciences, Michigan Technological University
- Units
- ISRO
- Keywords
- Aerial Survey, Beaver (Castor canadensis), Ecology, Gray Wolf (Canis lupus), Isle Royale National Park, Mammals, Michigan, Monitoring, Moose (Alces alces)