Breeding Season Home Range and Habitat Use of Mexican Spotted Owls ( Strix occidentalis lucida ) Below the South Rim of Grand Canyon National Park

Mexican Spotted Owls (Strix occidentalis lucida) below the South Rim of Grand Canyon National Park exhibit a strong preference for limestone cliffs within their breeding season home ranges, contrasting with observations in Utah where sandstone cliffs dominate nesting sites. The study, conducted from 2004 to 2005, used radio-tracking of five adult male owls to estimate home range sizes averaging 355 hectares (minimum convex polygons) and 372 hectares (90% fixed kernels). Owls demonstrated limited use of adjacent forested plateaus, focusing instead on narrow rocky canyons. Habitat selection analysis revealed a disproportionate use of limestone cliffs, which were central to their home ranges and nest sites. The research also identified core conservation zones of approximately 40 hectares around nest sites, aligning with adaptive kernel 30% isopleths. This study provides critical insights for the Mexican Spotted Owl Recovery Plan by delineating key habitat features essential for their breeding season survival.

Bowden, T. S., Ferguson, J. M., Ward, R. V., Taper, M. L., & Willey, D. W. (2015). Breeding Season Home Range and Habitat Use of Mexican Spotted Owls ( Strix occidentalis lucida ) Below the South Rim of Grand Canyon National Park. The Wilson Journal of Ornithology, 127(4), 678–689. https://doi.org/10.1676/15-004.1