Ecology of the wolverine in northwestern Montana

Abstract

A population of wolverines was studied in northwestern Montana for 5 years (1972–1977). Twenty-four wolverines were captured in live traps, individually marked, and released. Ten individuals were recaptured 74 times. Twenty wolverines were fitted with radio transmitters and 576 relocations were made over a 4-year period. A minimum population size of 20 was estimated for the 1300-km² area, or one wolverine per 65 km². The population was believed stable. This stability was maintained by mortality and dispersal. Wolverines utilized relatively large areas. The size and shape of ranges were not affected by rivers, reservoirs, highways, or major mountain ranges. The average yearly range of male and female wolverines was 422 and 388 km², respectively. Wolverines exhibited fidelity to a given area, but several individuals of both sexes made frequent long movements to other areas. In all instances wolverines returned to the same area. Ranges overlapped between individuals of the same and opposite sex. Territorial defense was essentially nonexisent. Wolverines scent marked to maintain spacing in time but not area. Wolverines appeared to select Abies cover types throughout the year; this selection was strongest in summer. In Montana, wilderness habitat coupled with more restrictive harvest regulations should provide for secure wolverine populations in the foreseeable future.