Feeding ecology, home range and habitat use by the wild boar in a Mediterranean coastal area (central Italy)
This study described the behavioural ecology of wild boar in a Mediterranean coastal area, with particular reference to its diet, home range, activity patterns and habitat use. Food use, derived from the analysis of faeces, was compared to the availability of the main food resources. The results showed that boar selected energy-rich food items such as acorns, olives and pineseeds, and relied mainly on graminoids when these resources were not available. Olives and acorns were used according to their availability, whilst pine-seeds were heavily searched for even when their production was low. The availability of pine-seeds, acorns and olives was unpredictable; as a consequence, the diet of the wild boar in the MNP showed no seasonal pattern, depending on the temporally available food items. The greater production of energy-rich food items in 1991-92, and the low availability of these foods in the following two years, was likely to have influenced body weights of boar, number of females breeding and litter size. The lack of high-energy food in winter 1992-93, the drought that hardened the soil in the following months and hampered rooting activity, together with the increased population density, were probably the main factors responsible for mortality amongst boar. Radiotelemetry allowed the estimate the home range size, activity patterns and habitat use. The results showed that home range decreased and the amount of activity increased during 1993, characterised by food shortage, high density of boar and high mortality. It was suggested that wild boar adopted strategies to cope with starvation and drought by (i) drastically reducing the size of their home range whilst slightly increasing the amount of activity for foraging in a smaller area, and (ii) shifting to habitat types, like meadows and olive-groves, that provided the only available food i.e. graminoids. No sex-related differences in home range size were found in this study. This finding was attributed to the fact that none of the 10 radiotracked females bred in 1993.