We tested the hypothesis that free-ranging white-footed mice (Peromyscus leucopus) and northern short-tailed shrews (Blarina brevicauda) reduce the survivorship of acorn weevils (Coleoptera: Curculionidae) overwintering in forest soils. Field exclosures differentially excluding these and other vertebrate insectivores, in combination with translocation of individual shrews from one site to another, were employed over 2 winters. The presence of small mammals led to a significant reduction in survivorship of weevils, but no effect due to density of shrews or presence of other potential predators (e.g., birds) was detected. These results are consistent with the hypothesis that these small mammals, through their consumption of weevils, have a positive effect on oak populations, and thus can affect forest composition and functioning.