Habitat Patch Size and Local Distribution of Burrowing Owls (athene Cunicularia) in Argentina

– Habitat quality and landscape structure are key factors that determine the distributions of animals. The general characteristics of the habitat of Burrowing Owls (Athene cunicularia) have been well studied, but little is known about how landscape structure affects this species. Other studies have suggested that food resources for owls should be higher in small patches because of increased edge and proximity to dense vegetation, and predation risk should be lower in large patches. We examined the relationship between patch occupancy by owls and the size of habitat patches produced by grazing of colonial, burrowing rodents, plains vizcachas (Lagostomus maximus, Chinchillidae), in central Argentina. We investigated the hypothesis that patch size influences prey availability for owls by comparing arthropod abundance in habitat patches of different sizes. We also examined the relationship between habitat patch size and vegetation characteristics of the patch. Vizcacha colonies occupied by owls had significantly smaller grazed areas than unoccupied colonies. Abundance and biomass of arthropods were not different among patch sizes or ______________ Corresponding author.