Session 1, Abstract 2

RAPID ASSESSMENT OF HABITAT SUITABILITY FOR BURROWING OWL RELOCATION

Kirra Connolly●*, Tanner Mathews● and Sarah Hennessy∆ (Mike Mooring● ), ●Point Loma Nazarene University, Department of Biology, 3900 Lomaland Drive, San Diego, CA 92106 and ∆ Institute for Conservation Research, Zoological Society of San Diego, 15600 San Pasqual Valley Road, Escondido, CA 92027.

Western burrowing owls (Athene cunicularia) used to be commonplace throughout San Diego County less than 50 years ago, but habitat loss from urban development has left the last remaining breeding population at risk of extinction. As part of a multi-year project to reintroduce burrowing owls to other sites in San Diego, we conducted ‘rapid assessments’ to identify the most suitable locations for the establishment of additional populations. We assessed the Rancho Jamul Ecological Reserve and five other sites using multiple survey techniques to determine habitat suitability, predation risk, and prey availability. Survey techniques included baited camera traps to sample rodent prey abundance, pitfall traps to sample insect prey abundance, transects to measure gopher and ground squirrel burrow density, scat collection to estimate coyote abundance, and raptor surveys to estimate raptor predation risk. We generated a ‘habitat suitability index’ using a landscape-scale habitat suitability model, and generated spider plots with customized axes to visualize the values of 10 variables at each site. Analysis of these plots reveals the restoration needed to optimize each site for successful owl breeding. In conjunction with management considerations, these results will contribute to making the final site selection for upcoming reintroduction of burrowing owls.

Logo by Rooks