Data from: Natal vs breeding dispersal: behavioural tactics in first-time breeder roe deer females during mating

By spatially segregating opposite-sex related individuals, natal dispersal is a widespread inbreeding avoidance mechanism. However, little is known about the alternative behavioural tactics that philopatric individuals employ to avoid inbreeding. When natal dispersal is partial and not sex-biased, females may perform reproductive excursions outside of their usual range. As a form of breeding dispersal, this could represent an alternative tactic to reduce the likelihood of mating with close relatives. To investigate this interplay at the individual level, we analysed the spatial behaviour of 90 first-time breeder roe deer (Capreolus capreolus) females. From intensive GPS monitoring, we classified individuals as either philopatric or disperser, and then identified excursions during their subsequent first mating season. While philopatric primiparous females were, on average, somewhat more likely (ca. 30%) to perform an excursion during the rut than dispersers, this difference was not significant. However, philopatric females performed excursions that were 52% farther, on average, than females that dispersed. Because philopatric females likely live in close proximity to related males, their father in particular, our results indicate that reproductive excursions could mitigate the risk of incestuous matings. This constitutes a first demonstration of interplay between natal dispersal and a specific form of breeding dispersal in a mammal.