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Featured Article

Voles are key mammals in understanding how social interactions can affect large-scale population processes. Previous studies have shown that at high population densities, meadow voles (Microtus pennsylvanicus) have a lower proportion of breeding animals, higher average corticosterone levels, and can be limited by female territorial spacing. Based on this, we compared corticosterone levels and spatial use between breeding and nonbreeding free-ranging adult meadow voles within populations. We measured intrasexual spatial overlap to examine if breeding females minimize occupying the same areas as other females, and noninvasively assessed corticosterone levels using fecal corticosterone metabolites (FCMs). We found that female meadow voles have much lower intrasexual spatial overlap than males, even though both sexes have similar range sizes, and that females have generally higher FCM levels than males. However, breeding and nonbreeding females did not differ from one another in spatial use or in FCM levels. Conversely, reproductive classes of males differed greatly in all measures: nonbreeding males had FCM levels that were two times higher than those of breeding males, occupied a smaller range, and had lower spatial overlap, indicating they were moving less widely than breeding males. We additionally validated an enzyme immunoassay for...