An assessment of the local impact of native predators on an established population of British water voles ( Arvicola terrestris )

Abstract

There is a considerable amount of literature on the diet and effect of feral American mink Mustela vison on the distribution and abundance of water voles Arvicola terrestris in Britain. Few recent studies, however, have attempted to examine the occurrence of water voles in the diets of native predators. Fox Vulpes vulpes scat and grey heron Ardea cinerea pellets were collected during winter 2003–2004 at a location known to contain a large number of water voles. These scats and pellets were subsequently analysed to determine the frequency of water vole occurrence in the diet of these opportunistic predators. Water vole remains were found in 30% of fox scats analysed and accounted for 13% of the total weight of scats. A total of 18% of heron pellets contained the fur of water voles in addition to the fur of four other rodent species. The potential role of native predators in the loss and fragmentation of site-specific populations of water voles in Britain is further discussed.