Observations on the winter ecology of Red Fox (Vulpes fulva) on South Manitou Island, Michigan

TitleObservations on the winter ecology of Red Fox (Vulpes fulva) on South Manitou Island, Michigan
Publication TypeReport
Year of Publication1977
AuthorsStockwell JE, Gannon JEdward
Pagination22 pp.
InstitutionUniversity of Michigan Biological Station
CityPellston, MI

The red fox population of South Manitou Island included approximately five to seven individuals in March 1976. Since no previous fox population records are available for the island, we cannot determine if this represents an increase or decrease in population density, although it appears fairly high in relation to island size. The population will naturally fluctuate in response to changes in food availability. Winter food sources for red fox consisted primarily of apples, edible flotsam (mainly alewives), and rabbits, supplemented with mice and bird life. There was no clear evidence that gulls were used as a food source during March. Range and movement of the red fox involved the entire island, but activities were most heavily concentrated in the northern portion. The proximity of hunting and denning areas to the gull colony makes fox-gull interaction inevitable. Easy accessibility of the colony and its concentration of prey (gulls) is probably the main motivating factor for gull kills, rather than fox population size. Scat samples did not include any identifiable gull remains, which suggests that fox prefer or have easier access to other food items during winter. If the National Park Service wishes to protect South Manitou Island as a wilderness area, both fox and gull populations should be permitted to determine their natural ecological balance without human intervention. However, if preservation of the gull colony is a more valuable goal, the Park Service may wish to institute a management program to eliminate the fox population on the island.