A Long-Term Study on the Dynamics of Guild Structure among Predatory Vertebrates at a Semi-Arid Neotropical Site

Abstract

For 48 mo we monitored diets and populations of 10 species of predatory vertebrates (two foxes, four falconiforms, and four owls) in semi-desert scrub at Auco, Chile. Pellets (birds) and feces (foxes) collected monthly contained identifiable remains of small mammals, birds, reptiles, amphibians, large insects, other arthropods, and (in some fox feces) fruits. For non-mammalian prey, seasonal variation in availability appeared to be more prononced than longer-term variation. In contrast, availability of the eight species of small mammals varied relatively little between predators' breeding and non-breeding seasons but declined by an order of magnitude through the first 3 yr of the study