Tetra Tech performed the first ever survey for large mammals at Edwards Air Force Base, a 301,000-acre facility in the Mojave Desert of southern California, to determine the relative abundance of large mammal species and identify any patterns of seasonal distribution or habitat use.

The study consisted of four seasonal surveys, with sampling effort allocated between habitats relative to the sizes of the habitats within the Base. To provide a thorough survey of large mammals and reduce potential biases from different techniques, four complementary field methods were used: transects, track stations, photo stations, and spotlight surveys. In each quarterly survey, 18 1-km long transects were used to identify large mammal tracks, burrows, and scat (feces). Forty track stations, baited with scented tablets, were used to collect track impressions in fine powder (diatomaceous earth). Ten photo stations consisting of motion-triggered cameras aimed at scented bait were used to monitor large mammals nearly continuously from winter through fall. Four 50-km long, nighttime spotlight surveys of different areas of the Base were conducted during each quarter to identify large mammals from vehicles.

The study confirmed the presence of eight species of large mammals on Edwards AFB: the coyote, desert kit fox, gray fox, domestic dog, bobcat, raccoon, American badger, and ringtail. Based on all techniques, the coyote, domestic dog (including feral dogs), kit fox, and gray fox were the most frequently observed large mammals. Other species potentially occurring on Base, namely mountain lion, western spotted skunk, and long-tailed weasel, were not detected.