Habitat selection by elf owls and western screech-owls in the Sonoran Desert

摘要

Little is known about habitat selection by elf owls (Micrathene whitneyi) and western screech-owls (Otus kennicottii). From 1994 to 1996 in the Sonoran Desert, I used point counts and nest searches to examine habitat selection by both species at multiple spatial scales. The abundance of both species had a positive association with percent cover of washes and mesquite (Prosopis spp.) at the scale of the study area. At both the scale of the study area and the nesting area, elf owls selected areas with high densities of mature saguaros (Carnegiea gigantea) and saguaro cavities. Elf owls nested only in woodpecker cavities in saguaros, whereas western screech-owls nested in both saguaro cavities and in natural cavities in mesquite. Western screech-owls nested nearly exclusively in gilded flicker (Colaptes chrysoides) cavities when they nested in saguaros. Patterns of nest cavity selection by elf owls suggest they may choose cavities that provide thermoregulatory advantages. I give management recommendations based on my findings.