SPACE USE, FORAYS, AND HABITAT SELECTION BY CALIFORNIA SPOTTED OWLS (STRIX OCCIDENTALIS OCCIDENTALIS) DURING THE BREEDING SEASON: NEW INSIGHTS FROM HIGH RESOLUT
Rachel V. Blakey; The Institute for Bird Populations/University of Missouri; PO Box 1346, Point Reyes, CA, 94956; (626) 660-8049; rachelvblakey@gmail.com; Rodney B. Siegel, Elisabeth B. Webb, Colin P. Dillingham, Rachel L. Bauer, Matthew Johnson, Dylan C. Kelser
Fauna of late-seral stage forests historically have been difficult to detect and track in rugged terrain, leading to challenges in movement characterization and conservation. We investigated movement of a late-seral specialist of conservation importance, the California Spotted Owl (Strix occidentalis occidentalis) using automated GPS loggers affixed to 15 owls in the northern Sierra Nevada, California. We used > 17,000 locations from individual owls to characterize home range size, movement distances, habitat selection (roosting and foraging) and use of the US Forest Service's designated Protected Activity Centers (PACs) during the breeding season (April-August). Roosting and foraging owls selected stands with high canopy cover and large trees at multiple spatio-temporal scales. PACs protected less than one quarter of foraging space use (volume of use) and fewer than half of observed roosts during the breeding season. Previously undocumented foraying behavior was recorded for non-breeding female owls, which travelled farthest of all owls and visited up to six PACs during a single breeding season. Given the owls' selection for later seral forest and tendency to travel long distances, the limited habitat protection afforded by the current PAC regime may be inadequate for this wide-ranging species.
Ecology and Conservation of Birds III