FERRUGINOUS PYGMY‐OWLS IN THE SONORAN DESERT

摘要

Ferruginous Pygmy-Owls (Glaucidium brasilianum) are small diurnal birds of prey that have declinedto endangered levels in southern Arizona, USA. We assessed resources important to habitat selectionand reproductive performance of pygmy-owls at five spatial scales across broad gradients in vegetationstructure and aridity in the Sonoran Desert. Resources at the nest-cavity scale explained more varia-tion in selection and performance than those at larger scales, highlighting their importance for conser-vation. At these small scales, owls selected nest cavities with smaller entrances, larger volume, greaterheight, and orientations that produced cooler microclimates in the hottest regions of the study area,and these choices all promoted higher performance.