West Mojave Plan FEIR/S - Desert Managers Group

Canine Predators: This includes coyotes, kit foxes, and feral dogs, the latter of which isnot a “natural” predator 12 . In 1982, Luckenbach concluded coyotes were probably the majorpredator of adult desert tortoises. Turner et al. (1997) determined that most failed tortoise nestswere excavated by coyotes or kit foxes, but no data were presented (Boarman 2002). Turner andBerry (1985) reported that 76 of 159 (48%) tortoise nests at the Goffs Study plot in the EastMojave were lost to kit foxes and other predators. During his three-year study at the DTNA inthe early 1990's, Peterson (1994) concluded that coyote predation was the main mortality factorobserved. In 1998 and 1999, 47% and 12%, respectively, of nests studied at Twentynine PalmsMarine Corps Base were dug up, probably by kit foxes (Bjurlin and Bissonette 2001). Predationby kit foxes and coyotes on tortoises may increase during periods of drought, when their normalprey base of small mammals is no longer available (Peterson 1993, 1994; Karl 2002).Feral dogs also injure and kill desert tortoises, and are relatively more common adjacentto urban and rural communities than elsewhere. Domestic dog sign was found on 88% of thesites surveyed in urbanizing areas (LaRue, unpublished data) and on 75% of the transectssurveyed in Lancaster (Tierra Madre Consultants, Inc. 1991). Comparatively, dog sign wasobserved on only 6 of 1,572 (i.e.,