Ecological Studies of Wolves on Isle Royale - Annual Report 1983-1984 (Covering the twenty-sixth year of research)
Peterson RO. 1984. Ecological Studies of Wolves on Isle Royale - Annual Report 1983-1984 (Covering the twenty-sixth year of research). Department of Biological Sciences, Michigan Technological University. Houghton, MI
In 1983-84 the wolf population of Isle Royale stood at 24, in spite of considerable turnover and changes in all three wolf packs. All three packs reproduced in 1983. The 1984 population included 10-11 pups, implying 39-43% mortality among animals present in 1983. Territorial overlap and conflicts continued in 1984; the Harvey Lake alpha female was killed by the West Pack II during the winter study. The moose population appears to have declined slightly to less than 800 animals, although the long-term trend for moose is expected to remain upward. A reduced cohort of 1983 calves appears to explain the slight decline. It remains to be seen if lower recruitment resulted primarily from loss to wolves or if it is partially attributable to the very young age structure of the population. Midwinter mortality to wolves continues to be very low, with wolves relying largely on old adult moose exhibiting a very high incidence of arthritis. The 1983 calves continued to exhibit the low vulnerability to wolves in winter that has been characteristic of recent cohorts. We expect continued growth of the moose population in spite of a lower rate of increase caused by wolf predation.
- Type
- Published Report
- Authors
- Peterson, Rolf
- Date of Issue
- 1984-05-15
- Publisher
- Department of Biological Sciences, Michigan Technological University
- Units
- ISRO
- Keywords
- Aerial Survey, Ecology, Gray Wolf (Canis lupus), Isle Royale National Park, Mammals, Michigan, Monitoring, Moose (Alces alces)