Mating-related movements of male brown bears on the periphery of an expanding population

Use of habitat and resources of large carnivores living at the expansion front of a population can differ considerably from those living in core areas. Using GPS (global positioning system) telemetry, we studied movements of male brown bears living in the northwest edge of the Alpine-Dinaric-Pindos population in Slovenia and Italy, 2005-08. Because there was a steep gradient of female densities in the periphery of the population and females occurred only in a small portion of the area used by males, we could test how the distribution of breeding females affected the spatial distribution and movements of male brown bears. The home-range size of the males in our study was inversely related to female densities. During the mating season we observed directed movement from the periphery of the population with low female densities toward the core area with higher female densities. Our observations suggest that this strategy allows even males living at the periphery of the population, where no females were know to occur, to take part in reproduction.