Island Fox Totally Explained

Everything about The Island Fox totally explained

The Island Fox (Urocyon littoralis) is a small fox that's native to six of the eight Channel Islands of California. It is the second smallest fox species in the United States. There are six subspecies of the fox, each unique to the island it inhabits, reflecting its evolutionary history. Other names for the Island Fox include Coast Fox, Short-Tailed Fox, Island Gray Fox, Channel Islands Fox, Channel Islands Gray Fox, California Channel Island Fox and Insular Gray Fox.

Taxonomy and evolution

The Island Fox shares the Urocyon genus with the mainland Gray Fox, the species from which it's descended. Its small size is a result of insular dwarfism, a kind of allopatric speciation. Because the Island Fox is geographically isolated, it has no immunity to parasites and diseases brought in from the mainland and is especially vulnerable to those the Domestic Dog may carry. In addition, predation by the Golden Eagle and human activities devastated fox numbers on several of the Channel Islands in the 1990s. Four Island Fox subspecies were federally protected as an endangered species in 2004, and efforts to rebuild fox populations and restore the ecosystems of the Channel Islands are being undertaken.
There are six subspecies of the Island Fox, Initially, fox populations were located on the three northern islands, which were likely easier to access during the last ice age—when lowered sea levels united four of the northernmost islands into a single mega-island (Santa Rosae) and the distance between the islands and the mainland was reduced—it is likely that Native Americans brought the foxes to the southern islands of the archipelago, perhaps as pets or hunting dogs.
Based on the limited fossil record and genetic distance from its Gray Fox ancestors, the northern Island Fox subspecies are probably the older subspecies, while the San Clemente Island Fox has been only resident on its island for about 3,400–4,300 years, and the San Nicolas Island Fox established itself as an independent group about 2,200 years ago. The Santa Catalina Island Fox is potentially the most recently evolved subspecies, having been on its island for about 800–3,800 years. The fox didn't persist on Anacapa Island because it has no reliable source of fresh water; Santa Barbara Island is too small to support the food demands of the fox.

Description

The Island Fox is much smaller than the Gray Fox, roughly the size of a House Cat, and is the second smallest of all foxes after the Fennec Fox. Typically the head-and-body length is 48–50 cm (18–20 in.), shoulder height 12–15 cm (4–6 in.), and the tail is 11–29 cm (4–11 in.) long, which is notably shorter than the 27–44 cm (10–17 in.) tail of the Gray Fox. The Island Fox weighs between 1.3 and 2.8 kg (2.8–6.2 lb.). The male is always larger than the female. The largest of the subspecies occurs on Santa Catalina Island and the smallest on Santa Cruz Island. Golden Eagle predation, discovered when foxes were radio-collared and monitored, proved to be the cause of the high mortality rates. Golden Eagle predation is the primary cause of Island Fox mortality. The Golden Eagle was an uncommon visitor to the Channel Islands before the 1990s according to the National Park Service records, and the first Golden Eagle nest was recorded on Santa Cruz Island in 1999. Biologists propose that the eagle may have been attracted to the islands in the 1960s after the decline of the Bald Eagle. The Golden Eagle replaced the Bald Eagle and began to feed on feral pigs due to the decimation of the local Bald Eagle population due to DDT exposure in the 1950s—the Bald Eagle would have deterred the Golden Eagle from settling on the islands while it subsisted on fish. This has occurred most likely as a result of a process known as 'apparent competition'. In this process, a predator, like the Golden Eagle, feeds on at least two prey, for example, the Island Fox and feral pigs. One prey item is adapted to high predation pressure and supports the predator population (for example pigs), whereas the other prey item (for example the Island Fox) is poorly adapted to predation and declines as a consequence of the predation pressure. It has also been proposed that complete removal of Golden Eagle may be the only action that could save three subspecies of the Island Fox from extinction.
Introduced diseases or parasites can devastate Island Fox populations. Because the Island Fox is isolated, it has no immunity to parasites and diseases brought in from the mainland and are especially vulnerable to those the Domestic Dog may carry. A canine distemper outbreak in 1998 killed approximately 90% of Santa Catalina Island's fox population. With the gradual recovery of the shrike population on San Clemente Island, the Navy no longer controls the foxes. Automobile fatalities have also been high on San Clemente, San Nicolas, and Santa Catalina Islands.

Federal protection

In March of 2004, four subspecies of the Island Fox were classified as a federally protected endangered species: the Santa Cruz Island Fox, Santa Rosa Island Fox, San Miguel Island Fox and the Santa Catalina Island Fox. The IUCN lists the entire species as critically endangered.
A key to the recovery of the Island Fox is the removal of the Golden Eagle from the Channel Islands, ecosystem restoration and disease control. To ensure survival of the Island Fox, Golden Eagles are being moved from the northern islands to the mainland. Maintaining and increasing the Bald Eagle population on the islands would help to displace the Golden Eagle. However, the program is extremely resource-intensive and is at risk for cancellation. Removal of feral pigs from Catalina Island and Santa Cruz Island is underway, removing both the golden eagles food and competition for the Island Fox. To eliminate the risk of disease, pets are not permitted in Channel Islands National Park. A vaccination program has been initiated to protect Catalina Island foxes from canine distemper.
Because the Channel Islands are almost entirely owned and controlled by either the Catalina Island Conservancy or the federal government, the fox has a chance to receive the protection it needs, including constant supervision by interested officials without the ongoing threat of human encroachment on its habitat.

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