Ranging behaviour and excursions of female roe deer during the rut
Résumé
Radiotracking of two roe deer Capreolus capreolus (1 female, 1 male) in a Mediterranean habitat (Matorrals) with a detailed analysis of the vegetation showed that within their annual home range the deers selected particular habitat types, according to the season. The northern slope was preferred by both animals. Comparatively to female, male had a larger annual home range (150 ha vs. 130 ha), composed of more widely scattered sites of preferred use in more seasonal vs variable habitat types. Habitat selection in different seasons was affected by several factors: i) in all seasons, abundance of Rubus ulmifolius and Rosa ssp., ii) strong winds, especially in winter, that caused the male to move to southern slope, iii) disturbance by hunting dogs in autumn that forced deers into one or two refuge zones, iv) aspect of deer biology, such as territory marking by the male and giving birth by the female, which modified not only behaviour but also use of space. Anecdotal evidence has suggested that, during the rutting period, female roe deer may undertake short excursions, outside of their normal home range, possibly to mate with a reproductive partner. To address this question, we analysed the ranging behaviour of 27 female roe deer Capreolus capreolus, equipped with GPS collars, inhabiting a fragmented landscape in France. We compared female movements during the rutting period with a non-rutting period over two summers using a recently published approach. Search intensity and home range size were significantly greater during the rutting period. The difference in home range size between the two periods was significantly greater in 2006 compared to 2005 and in open compared to closed habitat. We were not able to identify any influence of body mass on the difference in ranging behaviour between the two periods. Visual analysis of movement trajectories for 11 females revealed that 5 (45%) performed an excursion for a duration of a few hours to several days. We speculatively suggest that female rut excursions provide an opportunity for active mate choice in roe deer, where males are territorial, although we cannot rule out the alternative explanation that these movements are a means to avoid male harassment.