29th Annual Meeting and Symposium of the
Desert Tortoise Council, February 20-23, 2004
Abstracts

The Common Raven as a Threat to Desert Tortoise, West Mojave Desert, California

Blodwyn McIntyre
University of Redlands,1200 East Colton Avenue, Redlands, CA 92373-0999

The common raven (Corvus corax) is a subsidized predator of the desert tortoise (Gopherus agassizii). Raven predation on juvenile tortoises is believed to be one of the most important threats to desert tortoise. Although many threats to the desert tortoise are known, few, including raven predation, have been quantified, which is essential to conservation management. An area in the West Mojave Desert encompassing four Breeding Bird Survey (BBS) routes was chosen for study. Raven population increases since the 1970's were calculated for this area. Using GIS, features in this landscape identified as "raven attractants" were quantified. Spatial and statistical analyses were used to estimate and rank the importance of various "raven attractants" (landfills, water sources, urban areas, etc.) in their potential to increase local raven populations. The results of this study can be used in adaptive management of desert tortoise through management of "raven attractants".