Food habits of the stone marten (Martes foina) (Mammalia: Carnivora) in plain areas of Northern Italy prior to pine marten (M. martes) spreading

Abstract In the two last decades, the pine marten Martes martes has expanded in the River Po plain, causing the displacement of the stone marten M. foina from residual wooded areas. As a high degree of food niche overlap can favour exploitative competition and information about stone marten diet in Northern Italy was scarce, we analysed a sample of 181 stone marten faeces collected, prior to pine marten expansion (1997–1998), in the hay-lofts of farms located in the central plain of the River Po. Results were expressed in terms of both frequency of occurrence and mean percent volume, while seasonal variation was assessed by Compositional Analysis. The availability of small mammals was assessed by the analysis of 116 barn- and tawny owl pellets. The bulk of stone marten diet was made up of four main items in equal parts: fruit, birds, lagomorphs and small rodents. Seasonal variation occurred for fruits, which were eaten more in the ripening season, and birds, which were less preyed upon in spring/summer. I...