Contribution to the Life History of Sorex vagrans in Montana

During the period extending from October, 1948, through the first part of September, 1950, and the summers of 1951 and 1952, the author collected shrews in western Montana for a study of the taxonomic relationships of the Sorex vagrans-obscurus group (Clothier, 1951). The present study is based upon 306 specimens of Sorex vagrans monticola from this series for which sufficient amounts of life history data were available. Of these specimens, 188 were collected by the author, and 118 were obtained from other collectors. Seventy-seven were collected near Missoula, Missoula County, fifty-four were collected near Yellow Bay, Flathead Lake, Lake Co., and 137 were collected in Glacier National Park. An effort was made to collect shrews throughout the year, but most of the specimens were obtained during the spring, summer and early fall months. The numbers collected each month were: January—8, February—16, March—26, April—22, May—12, June—40, July—80, August—46, September—42, October—23, November—5, and December—6. Specimens were prepared as study skins and skulls whenever possible, and in all cases the bodies were fixed entire in an alcohol-formalin-acetic acid mixture (Guyer, 1936) for a few days, then preserved in 70 per cent ethyl alcohol.