Abstract

The diet of the Short-eared Owl (Asio flammeus) was quantified by analyzing 400 pellets collected in two agricultural landscapes of southern Chile (Osorno and Chahuilco). Diet composition fluctuated seasonally and included several species of small mammals, birds, and insects. Almost 80% of the annual biomass consumed was from two rodent species (Akodon olivaceus and Rattus norvegicus) and of a bird (Vanellus chilensis). No differences in the composition of the winter diets were detected between the two study sites, and the latter were similar in landscape structure and use by humans. Also, the size of hunting ranges used by Short-eared Owls was similar between the two sites (ca. 250 ha), with a prevalence of landscape elements such as meadows, wetlands, and agricultural fields. Nevertheless, Short-eared Owls concentrated their hunting activity ina reas with little human disturbance, such as vegetation fringes along roadsides, ungraded meadows, and untilled lands. Even though Short-eared Owls perched on the ground, they also used posts along roads and between properties as perches. Although suboptimal or marginal habitat for most other raptors, these human-dominated landscapes appeared to be valuable for the survival and persistence of Short-eared Owl populations, as long as their food and shelter remained unaffected.