We define perceptual range as the distance from which an animal can perceive key landscape elements, such as distant patches of forested habitat. We argue that perceptual range should be a determinant of not only dispersal success in unfamiliar or hostile landscapes, but also of several landscape-level ecological processes influencing population dynamics. To redress the absence of empirical information on perceptual ranges, we simulated the dispersal of forest-dwelling white-footed mice (Peromyscus leucopus) across an agricultural landscape by releasing mice into unfamiliar, hostile agricultural habitat at various distances from fragments of forested habitat. We found that these forest mice have a remarkably low perceptual range with regard to detecting their forested (core) habitat. Mice released into bare fields failed to even orient towards forested habitat as little as 30 m distant, while mice in crop fields appeared unable to locate for-st habitat as little as 10 m distant. These mice seemed to locate forested habitat by vision, despite the availability of non-visual cues. Future work will undoubtedly demonstrate vast differences in landscape-level perceptual abilities among animals, and show clearly that the ecological effects of a given landscape configuration will be influenced by the behavioral attributes of the species in question.