Microscale nest-site selection by the Burrowing Owl (Athene cunicularia) in the pampas of Argentina

Abstract

Habitat modifications have led many bird species to occupy areas with different characteristics, including human-altered landscapes. In this study, we analyzed how land use influences the nest-site selection at the microscale level by Burrowing Owls (Athene cunicularia) breeding in vegetated sand dunes, periurban areas, and agroecosystems in the Pampas of Argentina. We compared the characteristics of the nest site (percentage of open space) and the nest patch (distance to conspecific nests, tall vegetation and perches and number of perches) within and among the three land-cover types. In addition, we evaluated the breeding performance (nesting success and productivity) of owls nesting in these land-cover types. We found that nest microsite variables did not vary between owl-occupied and owl-unoccupied sites within nest patches, but they differed among land-cover types. Although nest patches differed in their availability of perches at each land-cover type, distance from the nest to the nearest perch did not vary between them. Distances to tall vegetation and to conspecific nests were highly variable and did not differ among land-cover types. Our results indicate that Burrowing Owls that inhabit the Pampas used a variety of land-cover types for nesting and showed little selectivity of nest sites and nest patches, thus reinforcing the idea that they are habitat generalists.