And Now, the Cycle Will Go On

Author: Anne Canright


On November 7, 2008, National Park Service biologist Tim Coonan crouched down in golden grass and unlatched the wire door of a small dog kennel. “Okay, M67,” he said softly. Out shot a tiny sharp-nosed fox sporting a black collar. Tentatively, he stopped to survey the scene, then glanced back over his shoulder at the kennel.

“You can’t go back in,” Tim said. “Don’t even think about it.” The fox looked around again at the sage-mottled grassland. “Anywhere is good. Anywhere.” Another lingering glance at the kennel and safety. “Dude, don’t go back. If you go back in, I’m going to kick you out.”

As the fox took one more look out and then back over his shoulder, this time quicker, Coonan coaxed him on: “Time to go. Time to go.” Then M67 made up his mind, and off he dashed, bounding in glorious long leaps up the scrubby slope. Coonan laughed with delight.

From the opening of the cage door to the fox’s disappearance over the crest of the hill, just one minute had elapsed. For Coonan, a 1981 Notre Dame graduate, it was a minute filled with cautious jubilation, marking the end of a decade-long experiment and one with high stakes — the survival of a species.

The story begins as long as 18,000 years ago, when gray foxes (Urocyon cinereoargenteus) from California’s mainland made their way to Santa Rosae, a land mass off Ventura, California, that in the intervening time, with a rise in sea level, has become the eight Channel Islands. Most likely, a pregnant female rafted across the narrow strait on storm debris, though it’s possible that Native Americans living on the islands brought foxes over as pets.

However they got there, there they stayed, and they quickly evolved into petite versions of their mainland relatives — standing 8 to 10 inches at the shoulder and weighing a mere 4 to 5 pounds, a third as much as a gray fox, smaller than a housecat.

These foxes also developed a looser, “island” lifestyle: more diurnal in their out-and-aboutness, denning under bushes rather than in holes dug into the ground, and ranging through diverse habitats to enjoy a cosmopolitan diet of fruits, insects, birds, eggs, crabs, lizards and small mammals. In the process they evolved into a genetically distinct species: Urocyon littorali.

In their island isolation, the foxes had a distinct advantage. Aside from humans, they had no natural enemies. Nothing took them; they were completely safe. For millennia.

The disappearance

Tim Coonan arrived at the Ventura, California, mainland headquarters of what is now Channel Islands National Park in 1992 from his previous park service jobs at Canyon de Chelly National Monument and Death Valley National Park. His first assignment was a terrestrial monitoring program for the four northern Channel Islands that make up the national park, to count everything from insects to reptiles to birds to mammals. The ecosystem seemed to be thriving and in balance. Just what a biologist wants to see.

But within a few short years, an alarming trend set in. Of the three national park islands that are home to island foxes — San Miguel, Santa Rosa and Santa Cruz — a precipitous drop in their population became apparent. Over five years, from 1994 to 1999, Santa Rosa fox numbers went from 1,500 to 15. San Miguel Island dropped from 450 to 15; Santa Cruz Island from 2,000 to 50 or 60. One researcher estimated that unless something was done, and fast, island foxes on Santa Rosa and San Miguel would be extinct within five years, on Santa Cruz within 12.

What was going on? One possible culprit was disease. Island foxes, being canids, are susceptible to rabies, which can be introduced by campers bringing dogs onto the islands illegally. But on all three islands at once? Not likely. Another possibility was a decline in their food supply, but surveys showed no such thing.

What about predation? A stealth predator, for example. One that arrives on the wing, dines and then departs over the water, leaving only a carcass as a calling card.

In November 1998, once the decline was noted, use of trackable radio-collars allowed examination of any foxes that no longer showed any movement. Thanks to that telemetry, the culprit was identified. It was Aquila chrysaetos, the golden eagle. A few months later, nesting pairs were discovered on Santa Rosa and Santa Cruz.

“No one had any clue that goldens could or would start making a living out here,” says Coonan. Historically, they’d been kept away by fish-eating bald eagles, but DDT and persecution had eliminated our national bird from the islands by the mid–20th century.

Another significant human interference was the introduction of non-native animals to the islands starting in the 1800s: pigs, sheep, cattle. As late as the early 1900s, San Miguel was overrun with sheep, which erased the native vegetation, leaving grassland and sand — scant cover for a fox caught in a golden eagle’s scope. On Santa Cruz, feral pigs, and on Santa Rosa, elk and deer — or their young, at any rate — offered up a bounty of other dining options. When eagles began not merely to visit but actually to nest on the islands, however, piglets and fawns weren’t always available. Foxes supplemented the menu nicely.

With the free-floating predators now known to be nesting on the park islands, there was literally no time to lose. In April 1999 — when biologists still thought there were at least several dozen foxes on each of the three islands — an ad hoc island fox recovery team was convened, experts in such areas as island fox biology, carnivore disease, raptor biology and captive breeding and reintroduction. The group consensus was swift and firm: if the foxes had any chance of surviving, they would have to be taken into captivity. Not only that, but the golden eagles would have to be removed from the islands, along with their exotic prey base of pigs and cervids — no small task.

Within one month, two cyclone-fence pens had been constructed on San Miguel Island and a pair of foxes had been captured and installed in their new quarters. By the fall, all the remaining wild foxes on the island (save one, which eluded capture for another two years) had been taken into captivity. Ten females and four males. A like strategy was put in place on Santa Rosa, and a looser one on Santa Cruz. It was now up to these individuals to bring their subspecies back from the brink.

“It was a huge decision,” says Coonan. “It meant that on two islands there would be no foxes at all in the wild; all of them would be in captivity. And whatever happened in captivity would determine whether there would be a wild population again.”

Pairing off

It is late January 2009. I am standing with Coonan and Ian Williams, the half-time resident ranger, at what Coonan calls “the scene of the crime” — a San Miguel Island ghost town of 11 enclosures, each a 5-foot-tall, 600-square-foot chain-link pen, in a protected spot called Willow Canyon.

“Sometimes when I come down to these pens, I think, ‘Did I dream this? For 10 years, did we do this?’” Coonan says, shaking his head. “Because before that, we were monitoring island foxes, and they were fine, and now we’re monitoring them, and they’re good, but for this 10-year period we were heavy-duty into captive breeding and worrying about the health of those individual animals. Feeding them. Vet workups every year. Vaccinations. It was an incredible amount of work.”

Just because you put two foxes in a pen together doesn’t mean they’ll breed. And in that sense, the program really was a big experiment. “When we went into it,” Coonan says, “we didn’t have a clear idea what would be required. In hindsight, many of our decisions turned out to be right, but that may be more a matter of luck, in that we were lucky to be working with a species that was fairly prolific. We didn’t have to do anything strange.”

What they did do was carry out genetic testing on the foxes, then pair males and females to produce the sturdiest blood lines possible. “We had a rule of thumb: if a pair didn’t reproduce within two years, we split them up and paired them with someone else.” Some animals, he says, “went through four or five mates and never produced.”

Male aggression was a problem, though it was found, too, that December-May pairings (older females with younger males) didn’t take, and once kits started coming along, wild-born females didn’t want much to do with captive-born males. In the end, only eight of the original 15 San Miguel foxes reproduced, two males (out of only four taken in) and six females. But reproduce they did, starting in 2000 with one litter, a boy and a girl. “The second year, 2001, it was like we hit the lottery because all five pups were boys. Now there were enough pairs to spread things around. We were ecstatic.”

Looking at these decrepit enclosures, it’s hard to imagine the full-facility bustle of adult and young foxes, playing with their Kong pet toys, squirreling through plastic tubing, taking a snooze on little hammocks and high shelves, or pouncing after mice — part of the revolving feast they were fed daily: dog and cat kibble, insects, quails, nuts, fruits and vegetables, hard-boiled eggs and, yes, live mice.

“There’s all kinds of Machiavellian techniques for feeding mice to foxes: put them in Chinese takeout boxes, or PVC pipes with a rag in each end like a party popper,” says Williams. “When you’d toss them in they’d grab them right out of the air — they’d even meet you at the door.”

A happy fox is, potentially, a breeding fox. As the captive population grew, the next generation entered into the breeding arena as well. While not all the foxes bred, enough did — and ultimately 53 pups were born on San Miguel Island between 2000 and 2006.

Back to the wild

Coonan, Williams and I leave the “ghost town” and walk up a narrow trail onto the low central plateau of San Miguel, which is slowly being recolonized by the natural scrub of the island — coastal sage, lupine, buckwheat, locoweed. By 2004, Coonan says, with 40 animals in captivity and a new brood of pups imminent, “we’d really reached the maximum number of captive foxes we could handle, with the staffing we had.”

It was time to reintroduce the foxes into the wild.

By this time, bald eagles were being reintroduced to the islands and the translocation of golden eagles to lands beyond the Sierra Nevada was well under way. Elk, deer and feral pigs also were in the process of being removed from the islands. Nevertheless, the proposal that the reintroduction begin was met with resistance by some on the recovery team.

“There were people,” Coonan says, “who wanted us to keep foxes in captivity until all the golden eagles were gone, which would have meant moving the captive breeding program to the mainland.” That, Coonan refused to do. “Reintroduction was a calculated risk, absolutely,” he says, but it was time to take that next step.

We see small cat-like prints in the soft dirt: foxes have passed this way. Farther along, a pile of scat lies at the intersection of two faint trails — a territorial marker. But we see no actual foxes.

“Right now,” Williams says, “they’re hunkering down. It’s pretty warm for them during the day, so they’re probably curled up under a bush.”

Coonan notes several high-activity periods. “Dusk is one, but also after midnight. And dawn. . . . They’ll be sleeping if they’re not hunting. Or in January, mating.”

Williams adds, “I always say, they eat till they’re tired, and they sleep till they’re hungry.”

Coonan stops at a rise that dips into a shallow, scrub-filled ravine. “This is the place. We’d release them in the evening here, with feeding stations to ease their transition, which we then closed off after a few weeks. Some bolted right out of the area. But still, this was a pretty good spot habitat-wise, protected, a lot of native plants.”

In the fall of 2004, 10 foxes were released on San Miguel, “mainly as pairs in the hope that they’d hook up. And they paired up right away. We had four pairs going by January or February of 2005, and we had 10 pups the next year from those pairs. It was just incredible.” The rest of the San Miguel foxes were released through 2007, and reproduction in the wild took off immediately.

On Santa Rosa, the last releasable fox — M67 — bounded to freedom in 2008. Although reproduction was a little slower to kick in on Santa Rosa, and a golden eagle or two were still wreaking some havoc, there too the numbers started noticeably to climb.

In late 2009, the population estimates had taken a leaping bound, with an estimated 320 foxes — close to carrying capacity — on San Miguel. “Numerically,” Coonan says, “we’ve reached biological recovery here on San Miguel, and will on the other islands probably within two or three years.”

Golden eagles remain a relatively minor worry. “I think, especially in the winter, we may have eagles showing up and taking a few island foxes, but leaving the island within a matter of weeks. And I think we can tolerate that.” Another potential threat is canid distemper virus, which a core group of foxes have been vaccinated against to preclude the possibility, however remote, of an epidemic wiping out the entire population.

We make our way to a knoll overlooking the north side of San Miguel. Williams pulls a collapsible antenna from his pack, extends its six arms, plugs it into a receiver and starts to wave it slowly across the landscape. He listens for pings, which are tied by specific frequency to individual animals.

This labor-intensive monitoring, together with round-the-clock automatic monitoring, will be ongoing — to identify any radio-collared animals that have gone into “mortality mode,” in order to evaluate the cause of death, and to follow individuals’ movements around the island. Each year in late summer, too, foxes are trapped for five nights running, to calculate their population size and density, and to collar, vaccinate and do a health check on the hapless trappees.

One interesting wrinkle to this story of recovery is that, for various reasons, the island foxes were not added to the federal endangered species list until 2004 — five years into the captive breeding experiment, and the very year their reintroduction into the wild began. Listing brought in a bit more funding for the program. It also, ironically, makes for what some are calling the quickest recovery of an endangered species.

Part of the reason for this speedy success, in addition to the foxes’ own reproductive vigor, is the setting. “If you solve something on an island, it pretty much remains solved,” says Coonan. “Remove pigs from Santa Cruz? They ain’t coming back.”

Saving the island

Later that night, after a full day soaking up the story of the island, I leave the bunkhouse to stand in the dark, under the pebbly shimmer of the Milky Way, the steady breeze pushing against my face. In the distance I hear crashing waves, rhythmic and insistent, and high-pitched yelps — the mating or birthing or battling cries of thousands of elephant seals, which themselves were gone from this island a mere 70 years ago. Voices in the night.

I think about how, in this place, for thousands of years, the foxes have danced after deer mice, wrestled each other in their mating ritual, rested under purple lupine, and taught their young the pleasures of seafigs and crabs.

It is comforting — important — to know and trust that, thanks to Coonan and the dedicated fox recovery team, that cycle will go on; that the foxes will continue to ply their wild existence on this windswept island; that the cages will eventually come down. Although, as Williams says, “This wasn’t just about saving the foxes; it was about saving the island.”

It’s like a Zen koan: Would San Miguel Island be San Miguel Island without the foxes? I don’t think so. The fox is the keystone. It is necessary. And, let us say however cautiously, it is here to stay.

Anne Canright is a freelance writer who lives in Monterey, California.
Photo from the National Park Service.