ISLAND FOX } Urocyon littoralis
HABITAT: Island foxes occur in virtually every habitat on the Channel Islands, including valley and foothill grasslands, southern coastal dunes, coastal bluffs, southern coastal oak woodland, southern riparian woodland, Bishop and Torrey pine forests, coastal marsh, and communities of coastal sage scrub, maritime cactus scrub, and island chaparral. Santa Cruz Island foxes have been known to prefer fennel grasslands and to avoid ravines and oak patches.
RANGE: The island fox is known only from the six largest Channel Islands off the coast of southern California. The endangered San Miguel Island fox, Santa Rosa Island fox, Santa Cruz Island fox, and San Clemente Island fox each hail from the island corresponding to their name.
MIGRATION: Restricted to their islands, these foxes do not migrate. Home-range sizes vary by habitat type, season, and sex of the animal; recorded home-range estimates range from 23.5 hectares in mixed habitat to 76.5 hectares in canyons on San Clemente Island.
BREEDING: Island foxes typically form monogamous breeding pairs and are seen together beginning in January and through the breeding season, which lasts from late February to early March. One to five kits are born in a den in the spring, after a gestation period of 50 to 63 days. They emerge from the den in the summer.
LIFE CYCLE: Island foxes reach sexual maturity at 10 months, and females usually breed within the first year. These foxes can live for up to 10 years in the wild, but four to six years is more typical. Pup and adult survival has been shown to vary from island to island.
FEEDING: The island fox's diet includes a wide variety of animal and plant materials and depends largely on availability. Principle foods include rodents, ground-nesting birds, arthropods, and fruits.
THREATS: The primary threat to the island fox is predation by invasive golden eagles. The species is also very vulnerable to canine distemper transmitted by domestic dogs, habitat fragmentation due to development, and habitat loss to introduced livestock and game species.
POPULATION TREND: The island fox declined catastrophically from the mid-1990s to the end of the century, but due to captive breeding, relocation of golden eagles, and reintroduction of bald eagles (to prevent the goldens from recolonizing), the populations of its subspecies have since grown. The San Miguel island population went from 450 in 1994 to 15 in 1999, growing to 40 wild and 26 captive foxes by 2005; Santa Cruz Island foxes declined from 1,465 in 1994 to 60 in 2001, but had become 150 wild and 62 captive foxes by 2005; the Santa Rosa Island population declined from 1,780 in 1994 to 14 in 1999, with numbers rising to 32 wild and 34 captive foxes by 2005. Though the population of the Santa Catalina Island fox has been studied only intermittently, sightings had dramatically declined by the summer of 1999; the subspecies' population has increased since its 2004 listing. By 2016, populations had recovered to the point that the Service proposed to remove San Miguel island fox, Santa Rosa island fox and Santa Cruz island fox from the endangered list, and to downlist the Santa Catalina island fox from "endangered" to "threatened."