Comparison of food habits and of nutrients in the stomach contents of summer- and winter-trapped voles (Microtus pennsylvanicus)

Abstract

Meadow voles (Microtus pennsylvanicus) have low fat reserves in winter. Since plant parts with high nutritive values are less abundant at this period, we hypothesize that voles must select different items or face a lower quality diet than during summer. Food habits determined from epidermal plant fragments of fecal matter showed that summer- and winter-trapped voles were using the same plant species though in somewhat different amounts. Nutritive constituents evaluated from stomach contents varied significantly by season. Stomach contents of winter-trapped voles had lower levels of protein and total phenolics and higher levels of total nonstructural carbohydrates. Forage quality ratios involving protein/total phenolics did not vary between seasons. These results suggest that overwintering voles of this study, trapped during low density, did not face obvious nutritive constraints. However, voles living under more crowded conditions could still face foraging constraints.