Island Foxes’ Future at Risk

Spanish settlers unwittingly began making an ecological bomb here a century and a half ago.

Turn-of-the-century sheepherders added to it. DDT-spraying farmers finished the job. The fuse burned until the last half of the 1990s, when the bomb took out thousands of docile and unwary island foxes.

The catastrophe has brought the island fox--one of the world’s smallest foxes but the largest mammal unique to California--to the brink of extinction in Channel Islands National Park.

While biologists try to restore an ecological balance upset by pigs, nonnative grasses and golden eagles, they’re using their weapon of last resort--captive breeding--to keep foxes alive on islands where they number as few as 15.

“It’s almost akin to stopping the bleeding,” said National Park Service biologist Tim Coonan, who has studied the house cat-sized foxes since 1993.

The fox’s future depends on finding the money for a multimillion-dollar recovery effort. But with a petition filed to put the fox on the endangered species list only a month ago, federal interest in funding long-term recovery efforts is far from guaranteed.

“We’re at a very iffy stage right now whether this going to happen,” said Gary Romer, a biologist who has studied island foxes since 1988.

The northern Channel Islands don’t look like a place where a fox or anything else would face extinction. Accessible only by boat or plane, the national park sees fewer than 100 visitors a day on average. Those who make the trip hike through rugged canyons, relax on pristine beaches and--if the notoriously windy islands aren’t too gusty--enjoy the quiet.

In this land of chaparral and wind-swept cliffs, the foxes enjoyed a 16,000-year stint of easy living. It began when their gray fox ancestors made it across the Santa Barbara Channel--possibly atop driftwood--to what was then a single island much closer to the mainland.

In making the crossing, the foxes ditched the coyotes, the mountain lions and anything else that might look upon them as a primary food source. Bald eagles ruled the skies, but they tended to hunt ocean prey.

The foxes “were top dog, so to speak,” said Romer, a postdoctoral associate at UCLA.

Thousands of years without predators caused island foxes to stop watching their backs--literally. Coonan said they tend not to watch the skies for raptors and are more active during the day than other fox species.

Romer said the foxes are also unusually docile.

“You can handle them without drugging them,” Romer said. “We even draw blood without knocking out these guys. Most carnivores wouldn’t put up with that at all-- they’d tear your hand off.”

Nine months after Romer began a collaring and monitoring program for Santa Cruz foxes in 1993, he found no reason for them not to be mellow. Not a single animal he tracked died until April 1994, when he found a collar, a carcass and some golden eagle feathers.

“I thought, ‘Wow, neat--so golden eagles do take foxes now and then,’ ” Romer said.

Seventeen months later, barely 20% of the foxes Romer was tracking were still alive, and a boom in the population of golden eagles--spurred on by the cumulative effects of decades-long ecological changes--appeared to be the culprit in most of the deaths, he said.

Romer estimates that the islands--each of which has a distinct subspecies of island fox--had about 6,000 foxes in the early 1990s. He said the populations at San Clemente and San Nicolas have remained stable at roughly 800 and 500, respectively, but their combined numbers on the other four islands they call home have plummeted to about 300. On one island, Santa Catalina, about 100 foxes are left after a wave of canine distemper decimated the population.

The populations on the other islands--100 on Santa Cruz, as few as 50 on Santa Rosa and 15 on San Miguel--dropped because golden eagles made the crossing and began preying on unsuspecting foxes.

Coonan said what’s driving the eagles to the islands are hundreds of feral pigs, descendants of animals Spanish settlers let roam in the 19th century.

If it weren’t for DDT, bald eagles would have kept goldens from moving in.

The pesticide left eggshells brittle and wiped out the bald eagle around the Channel Islands by 1950. The golden eagle--more of a land-focused hunter than the bald eagle--was hit too, but federal protections for both species beginning in the 1970s allowed goldens to thrive in Santa Barbara County.

By the mid-1990s their population in the area was so great they expanded west into the Channel Islands.

Another man-made disadvantage for the foxes came in the form of nonnative grasses, which overwhelmed species like chaparral that provide cover. Ranchers brought in sheep and other animals that spread nonnative seeds often contained in their feed, Coonan said.

Biologists involved with the foxes plan to meet this month to agree on a plan for the fox’s long-term survival and begin lobbying for funding for it.

The Park Service did part of the work needed to restore the fox before officials even realized the species needed help. In the late 1980s and early 1990s it used traps, dog teams and hunters to rid Santa Rosa Island of about 1,400 feral pigs.

Getting thousands of pigs off the other islands will cost $3 million to $5 million, Coonan said.

Other elements are the captive breeding programs on Santa Rosa and San Miguel islands, which this spring helped bring into the world the first 11 island foxes born in captivity. Each program costs $100,000 a year, and Coonan is pushing to extend them 10 years and create another on Santa Cruz Island.