Food Habits of the Meadow Vole (Microtus pennsylvanicus) in Bluegrass and Prairie Habitats

We analyzed stomach contents to determine food habits of the meadow vole, Microtus pennsylvanicus, in two habitats in central Illinois, a bluegrass oldfield and a tallgrass prairie. Vole diets showed strong seasonal changes in both habitats. Voles in the bluegrass area ate mostly green shoots with increasing amounts of dicotyledons and decreasing amounts of monocotyledons as seasons progressed from winter to autumn. Seeds became important only in autumn and winter. Ambrosia, Bromus, Poa, Taraxacum, and Trifolium were the major plants eaten during the growing season. Preference indices showed that Trifolium was preferred and Poa was avoided in relation to their availability. Voles in the prairie consumed more dicotyledons than monocotyledons year-round; seeds and roots became important in autumn and winter. These voles ate primarily Andropogon, Lespedeza, Penstemon, and Solidago during the growing season. Preference indices for these species indicated that none were significantly preferred, but Andropogon was avoided. Seasonal shifts in food habits may help to account for seasonal changes in reproductive performance of voles, and differences in the availability of moderate to high quality food may explain differences in population densities between the two habitats.