How the little Channel Islands fox came back from near-extinction

A tiny fox on California’s Channel Islands has made a strong comeback from its path toward extinction, so much so that the US Fish and Wildlife Service may take it off the endangered species list, it was announced this week.

But the little fox’s story is a complicated one, illustrating the sometimes-fragile balance in nature that can be disrupted by human intentions and activities. It’s a good-news story for now, but conservationists warn of new threats tied to human activity.

The fox, about the size of a house cat and averaging some four pounds, mates for life and feeds on mice, ground-nesting birds, insects, and plants. As far back as anyone can remember, the fox inhabited the islands free of predators. Over thousands of years, genetically distinct subspecies of foxes evolved on six of the Channel Islands – San Miguel, Santa Rosa, Santa Cruz, San Nicolas, San Clemente, and Catalina.

But in more recent decades, another species – feral pigs descended from domestic stock – began populating the islands. This attracted golden eagles from the California mainland, which began feeding on foxes as well as pigs.

“Naïve to aerial predators, the foxes made easy targets, resulting in a rapid decline in population,” according to The Nature Conservancy. “The [Santa Cruz Island] fox population fell from 1,500 to fewer than 100 animals in less than a decade – a 95 percent reduction of the fox population.”

It was a classic case of a nonnative, human-introduced species – pigs – directly causing decimation of a native species. Canine distemper on Catalina Island (thought to have been introduced by a raccoon stowed away on a boat from the mainland) added to the overall loss.

In 2004, the little fox was officially listed as an endangered species under federal law on four of the islands (Catalina, San Miguel, Santa Rosa, and Santa Cruz), which required a recovery plan.

Since then, nonnative golden eagles have been relocated to northern California, pigs were killed by professional hunters, native bald eagles (more interested in fish than in foxes) were reintroduced, and a vaccination program was credited with reducing the incidence of distemper. The Island Fox Recovery Program – a partnership of The Nature Conservancy, the US Fish and Wildlife Service, the National Park Service, and the California Department of Fish and Wildlife – also included captive breeding of fox pairs.

As a result, the Santa Cruz Island fox population is back up from fewer than 100 to 1,354, according to the Fish and Wildlife Service, and the total Channel Islands fox population is an estimated 4,677.

“Due to the remarkable success of the Endangered Species Act, recovery actions by land managers and conservation partners have led to dramatic population increases on all four islands since listing, effectively bringing the species back from the brink of extinction,” Steve Henry, field supervisor of the Fish and Wildlife Service’s office in Ventura, Calif., said in a statement. “To date, it appears that this is the fastest population rebound due to recovery actions and ESA protections for any land mammal in the United States.”

As wildlife officials closely track the fox’s recovery from near-extinction, they warn of new threats involving another interspecies conflict – as the animals make their way into residential areas where they are increasingly found trapped inside trash bins, hit by cars, stuck in uncovered water containers, attacked by dogs, and killed by rat poison.

“In 2014 alone, at least 25 foxes died from human interactions; a majority of these having to do with trash cans,” the Catalina Island Conservancy reports. “Foxes are attracted to trash cans and sometimes get trapped inside. However, since many of the cans are located near rest stops and scenic lookouts, an even greater danger is the possibility of the fox being struck by a vehicle while running across the road to reach the trash cans.”

The conservancy is now raising money to buy animal-proof trash cans.