The purpose of this study was to examine some of the possible causes for the negative density-area relationship reported for the white-footed mouse, Peromyscus leucopus. I examined predation and food availability in three small and three large forest fragments. Giving up density trays and various odors were used to test the variation in foraging behavior in the presence of a predator odor. Nest boxes and counts of periodical cicada emergence holes were used to test the effects of an emergence of periodical cicadas on P. leucopus population densities. Predator odors had no effect on foraging behaviors. P. leucopus responded to indirect, but not direct, cues of predation. Estimated densities of periodical cicada emergence holes were strongly related to the relative population density of P. leucopus. Continued study of predation and food differences in forest fragments of different sizes is needed to further examine the negative density-area relationship of P. leucopus.