DIET OF THE BARN OWL (Tyto alba SCOPOLI 1769) FROM THE COPIAPO VALLEY, ATACAMA DESERT, CHILE
SUMMARY The Barn Owl (Tyto alba) is a nocturnal raptor species distributed from Arica to Tierra del Fuego in Chile. The diet of this bird is the best known of any raptor of Chile; it is based on small vertebrates, particularly rodents and birds. We studied the diet of the Barn Owl, by analyzing of pellets collected in Copiapo valley, located in the hyper arid Atacama Desert. This information was compared to available data from Chile and neighboring countries. Because of the environmental conditions of extreme aridity a low diversity of prey, typical of raptors from arid ecosystems, was expected. In the case of Tyto alba populations from the Atacama region, the most consumed species were rodents (76.7% specially Eligmodontia dunaris (27.3% Phyllotis darwini (24% and Abrocoma bennetti (12.4% Other preys corresponded to birds (17.8% and coleopterans (3.3% There was no significant correlation be tween frequency of prey and their body mass (r 2 0.229, p= 0.497) and between frequency of prey and their habitat (r 2 0.538, p= 0.088) indicating that this raptor does not select its preys by either body size or habitat. Regarding biomass, rodents contributed more significantly (95.3% than birds (3.5% with the largest individual contribution given by A. bennetti (60.1% and P. darwini (26.8% Both the Simpson (SI 0.1683) and Shannon (H' 0.8958) indices indicate that this species consumes a low diversity of prey, which is consistent with the observations for others raptors inhabiting on arid environments.