OCCUPANCY MODELS AND STABLE ISOTOPE ANALYSES INDICATE POTENTIAL COMPATIBILITY OF CALIFORNIA SPOTTED OWL CONSERVATION AND PRIVATE LAND MANAGEMENT.
Brendan K. Hobart; University of Wisconsin - Madison; 1630 Linden Dr., Madison, WI, 53706; (262) 422-8533; bkhobart@wisc.edu; Kevin N. Roberts, Brian P. Dotters, William J. Berigan, Sheila A. Whitmore, Martin G. Raphael, John J. Keane, R.J. Gutierrez, M. Zachariah Peery
California spotted owls (Strix occidentalis occidentalis) inhabit mixed-ownership landscapes throughout the Sierra Nevada but most previous research on this subspecies has occurred on public lands. Thus, relatively little is known about the impact of private lands - and forest management upon them - on California spotted owl ecology and conservation. Therefore, we conducted the first large-scale private-public cooperative study of California spotted owls inhabiting mixed-ownership landownerships. We surveyed 151 spotted owl territories from 2013 to 2017 within two study systems: one comprised primarily of public lands (national forests) where the owl population has declined over the last ~20 years and a set of study areas comprised mostly of private lands on which relatively high estimates of site occupancy were recently reported. Multistate occupancy models indicated higher occupancy and reproduction probabilities in the private-land dominated study area but suggested that such differences were the result of variation in topographic and land-cover conditions that may promote populations of key spotted owl prey species. Follow-up stable isotope analyses suggest a positive relationship between spotted owl population status and dietary proportion of early-seral associated small mammals (Thomomys and Neotoma spp.). Our research thus indicates that private lands may play a critical role in spotted owl conservation.
Ecology and Conservation of Birds III   Student Paper