Mink Movements and Populations on a Montana River

A mink (Mustela vison) live-trapping program was conducted on the lower Madison River near Three Forks, Montana, from 1955 to 1958 to obtain information on movements and populations. Marshall (1936) and McCabe (1949) delimited the approximate sizes of home ranges of mink females in certain habitats and seasons in Michigan and Wisconsin, respectively. Observations on individual mink movements have been reported by Hibbard and Adams (1957) in North Dakota and by Ritcey and Edwards (1956) in British Columbia. Since home range is known to be influenced by habitat (Burt, 1940), it seemed desirable to secure information for the Madison River population which is subjected to an annual harvest by commercial fur trappers. Also, it was desirable to compare age and sex ratios of live-trapped minks with those of minks commercially trapped. The writer wishes to extend thanks to Kenneth R. Greer and Fletcher Newby of the Montana Fish and Game Department for interest and guidance during the project. Also, thanks are extended to landowners in the study area and to commercial trappers who cooperated. The writer is indebted to Don C. Quimby, Montana State College, for his direction of the study and aid in preparing the manuscript. During the investigation the writer was employed by the Montana Fish and Game Department, under Federal Aid Project W-49-R.