A study of medium-sized carnivores was completed in 2005 by the Trust and the U.S. Geologic Survey’s (USGS) Biological Resources Division. Dr. Erin Boydston used several types of trapping and surveying techniques to learn about predators, especially the elusive grey fox, and to clarify the context of this community of wildlife. It is not often that you see gray fox anywhere in San Francisco. Over the last 200 years, as urban habitat has replaced native habitat, the city has seen most of its larger mammals disappear one by one, and even now species like the gray fox face the possibility of local extinction. The primary threat to the gray fox is the automobile.

Gray fox are the only fox species in the world that can climb trees. They prefer woody, brushy habitats, and eat a variety of foods. Their keen sense of smell and acute hearing help them locate small mammals, such as gophers and mice. Gray fox also eat fruit, plant materials, insects, and birds. Not only are they scarce in the Presidio, they are rarely seen due to their shy nature and nocturnal lifestyles.

Once widespread, gray fox are now confined to only a few natural areas within the city such as Glen Canyon Park, McLaren Park, San Bruno Mountains, Bayview Hill, and the Presidio, although sightings here are very rare.