Variation in the diet of the red fox in a Mediterranean area

The diet of the red fox Vulpes vulpes was studied in the province of Pisa, Central Italy, analysing both faeces (N = 1261 ; collected monthly for one year in nine areas) and gut contents (N = 330 ; collected between January and May in the whole province). Diet was very varied, and was dominated by vertebrates, especially mammals, and plants (especially fruit) whereas invertebrates were less abundant. Food of human origin was approximately a half of the diet. In late winter and spring, females ate more small mammals and invertebrates than males, whereas yearlings had diets similar to adults. The body fat and size were not related to the volume of any food item. Seasonal variation was large for most categories, vertebrates being eaten mainly in winter and spring, and fruits in summer and autumn. Invertebrates were eaten mainly in summer. Several of these trends could be explained by the availability of food, but small mammals were eaten less when they were presumably more abundant. Globally, the diet in rural areas was homogeneous, and very different from that in areas with little human intervention. Over the whole province, differences were limited to three secondary items of human origin. Grass and other vegetable matter in stomachs and in intestines were significantly related to the consumption of invertebrates, not to the presence of parasite worms in the intestines. The high consumption of fruits and of resources of human origin is a characteristic trait of the fox diet in this and other areas of Italy. Fruits may be a supplementary food item, whereas small mammals may be a key resource. Foxes ate more fruits when and where fox population density was higher. Reasons for these trends are discussed.