Flush responses of Mexican spotted owls to recreationists
The Journal of Wildlife Management
Mexican spotted owls (Strix occidentalis Lucida) occupy narrow canyons on the Colorado Plateau, some of which are subject to high levels of recreational activity. These activities represent a potential threat to owls, yet due to the confines of canyon walls, spatial restrictions on recreational activities would likely eliminate all activity within these canyons. We assessed factors that influenced flush responses (flush or no flush), flush distances, distances of avoidance flights, and behavioral changes of owls in response to a single hiker that approached roosting owls. Increased perch height decreased the likelihood that adults (odds ratio = 0.09) and juveniles (odds ratio = O. I 7) would flush in response to the presence of a hiker; having flushed previously the same day increased the likelihood of adults flushing on subsequent approaches (odds ratio = 6.83). Juveniles and adults were unlikely to flush at distances ~12 m and ~24 m from hikers, respectively, and neither age class was likely to alter its behavior in response to the presence of a hiker at distances ~55 m. Based on these response thresholds, placing a 55-m buffer zone around roosting sites would eliminate virtually all behavioral responses of owls to hikers, but would restrict hiker access to 80% of canyons occupied by owls. A less conservative 12-m buffer zone would eliminate 95% of juvenile and 80% of adult flush responses, and restrict hiker access to 25% of canyons occupied by owls.
Swarthout, E. C. H. and R. J. Steidl. 2001. Flush responses of Mexican spotted owls to recreationists. Journal of Wildlife Management 65:312-317.