Nitrogen and Carbon Concentrations in the Stomach Content of Bank Voles (Myodes glareolus). Does Food Quality Determine Abundance

We found that concentrations of nitrogen (N) in the stomach of voles varied between forest sites. Concentrations of nitrogen as well as the ratio of nitrogen to carbon (C) in stomach content were not different between the sexes or with season. Body mass varied between sites and between seasons but were unrelated to N concentration in spite that the body mass of voles in the spring season were on average 4.8 g heavier than in the autumn A positive relationship was found between N and C concentrations in the stomach content implying the diet quality could be related to this ratio. N concentrations in the stomach per unit body mass were positively and significantly related to catch per unit effort of voles. We suggest that sites with high N concentrations in stomach content and with higher NC-ratio imply better habitats that support higher population densities of voles.