Bruns Stockrahm, D.M. 1991. Distribution of small mammals in grasslands of western Minnesota with special emphasis on the prairie vole (Microtus ochrogaster), the northern grasshopper mouse (Onychomys leucogaster), the plains pocket mouse (Perognathus flavescens), and the western harvest mouse (Reithrodontomys megalotis). Final report submitted to the Minnesota Department of Natural Resources. 53 pp.
During the fall of 1990 and the summer of 1991, a total of 11 grassland study sites in Clay County and 6 sites in Lac Qui Parle County in western Minnesota were live trapped to locate populations of 4 rodent species: prairie voles (Microtus ochrogaster), northern grasshopper mice (Onychomys leucogaster), plains pocket mice (Perognathus flavescens), and western harvest mice (Reithrodontomys megalotis). Sites were generally monitored for small mammals with a 500-m transect of live traps placed at 10-m intervals. Traps were prebaited for 1 day then set open and checked during the 4 following days. A total of 15 prairie voles, 13 northern grasshopper mice, 1 (probable) western harvest mouse, and various nontarget species were captured. Prairie voles were always captured on dry prairie sites, and grasshopper mice were always trapped on sites with gravelly, coarse soils. Gravel and old quarry sites in western Minnesota should be checked further for grasshopper mice and protected in some way if they prove to be adequate habitat sites. We agree with the recommendations of the 1988 small mammal survey of the Minnesota County Biological Survey about burning in a patchwork pattern so as to maintain prairie patches with and without litter buildup to provide habitat for a variety of the target species. It is recommended that all 4 target rodents be considered species of "Special Concern", a label currently given only to the prairie vole. The plains pocket mouse and the western harvest mouse seem to be extremely rare in western Minnesota grasslands and perhaps should even be considered as "Threatened Species".