It’s a classic situation of the fox in the henhouse, only in this case the fox is a golden eagle, the henhouse is an island, and the hen is . . . well, a fox. A tiny little fox, only two-thirds the size of its mainland relative, the gray fox—”more kittenlike than fox-in-the-henhouse-like,” says Brian Walton of the Santa Cruz Predatory Bird Group. Walton is working with the National Park Service on San Miguel Island, the most remote of the northern Channel Islands, to sweep the henhouse free of golden eagles.

These birds are not native to the Channel Islands. Of course, it’s no problem for them to fly the 25 or so miles between the Ventura County mainland and Santa Cruz Island, and then do short hops to neighboring Santa Rosa and San Miguel Islands, all of which have their own unique subspecies of fox. In the past, such forays were kept in check by the presence of bald eagles; by the mid-1900s, however, these larger, fish- and bird-eating raptors had been all but eliminated from the California islands, victims of pesticides that weakened shells, chick predation by feral cats, and years of sport hunting and egg collecting. (At least 125 bald eagle eggs in collections around the country can be traced to nests on the Channel Islands.) The coast was clear, and sometime in the early 1990s, apparently, a small group of young goldens soared out over the water and found a tidy food source.

The birds probably fueled up at first not with foxes, but with wild pig carcasses on Santa Cruz Island. But what golden eagle would turn up its beak at a little canid frisking in the grasslands? Easy pickings.

The island fox, Urocyon littoralis, lives on the six largest Channel Islands (Santa Cruz, Santa Rosa, and San Miguel in the north; San Clemente, Santa Catalina, and San Nicolas in the south). Descended from the mainland gray fox (U. cinereoargenteus), it probably reached the northern islands by rafting across the water, perhaps as recently as 20,000 years ago; in the south, Native Americans likely brought the island foxes as pets. Once established on the islands, it evolved into the dwarf species—approximately as big as a housecat—we know today. It also changed its lifestyle, abandoning its preference for woodlands and moving into all habitat types, from chaparral to coastal sage scrub to grassland to dune communities, and becoming more of a generalist in food habits. An island fox dines on insects and fruit in season, supplemented by birds, eggs, carrion, mice, and the occasional amphibian or reptile. Island foxes will even climb trees to find food.

Island foxes live eight to ten years and can breed after their first year, though most breeding is done by older adults. They mate for life. Breeding commences in January, and a litter of two to five pups is born in late April. The pups remain in the dens until early summer, when they emerge to forage with their parents. The family stays together until the pups’ first winter.

The signs of something not-quite-right going on were spotted in 1995. Two years before, Channel Islands National Park launched a long-term ecological monitoring program for terrestrial ecosystems, conducting annual censuses of vegetation, reptiles, amphibians, deer mice and foxes (the only two significant mammals), and birds on the five islands within the park.

Monitoring of the foxes is accomplished via capture-mark-recapture methods. “Foxes are live-trapped in box traps, marked, and released,” explains Tim Coonan, a biologist with the National Park Service. “Traps are set out in large grids for five nights in a row during the summer, after pups have left the den. The ratio of marked to unmarked foxes is used to estimate the total number.”

In 1994, some 450 adult foxes were counted on San Miguel. The next year, the population on the west side of the island had crashed, among both adults and pups. At that point, says Coonan, “we didn’t know if it was just some sort of normal fluctuation.” But when the same thing happened on the east side of the island in 1996, “we knew something was wrong.” Biologists at the park now estimate that there are fewer than 30 adult foxes on San Miguel, with comparable declines of as much as 90 percent on the other two northern Channel Islands.

Once the severity of the population drop hit home, biologists got to work trying to figure out what was happening. Earlier investigations by the Arcata-based nonprofit Institute for Wildlife Studies had shown that predation by golden eagles was a primary cause of an island fox decline on the west end of Santa Catalina Island. In November 1998, park biologists put radiocollars on eight foxes—seven youngsters and one adult. Within four months, six of those foxes had died, four of them apparently at the talons of golden eagles. One of the victims, says Coonan, “really worried me; she was one of the oldest and most savvy foxes.” Because there are no native predators on the island, however, she had no built-in defenses.

This spring, Channel Islands National Park convened an island fox recovery team to develop a plan. The team recommended a two-pronged approach: removing the eagles from the islands and capturing the foxes on San Miguel and Santa Rosa Islands, both to safeguard them from further attacks and to institute a captive breeding program to increase their numbers.

In May, two foxes were taken into captivity in a pilot program, the aim being to determine what diet will work over the long run and to test out the holding pens. The foxes are baited with cat food and then must be transitioned to a slightly less rich diet consisting of dry dog food and vegetables, supplemented by frozen quail and hard-boiled eggs. The vegetables are spiced up with garlic powder to add interest—even foxes will turn up their noses at food that is too bland. Also, Coonan points out, “we want them to retain the ability to catch prey, so we deliver live mice in small boxes.” The foxes are curious animals and, intrigued by the fidgeting little container, they soon manage to get at the live prey.

In early August the construction of eleven 20x30-foot completely enclosed holding pens commenced on San Miguel, and as quickly as possible all the remaining foxes on the island will be captured. As of late September, 11 foxes were being held. “We know of at least four other foxes in the wild,” Coonan states, “and suspect there may be as many as ten. For a total population of about 20.” The pens will be scattered, with one family group billeted in each. Within five years, Coonan hopes to begin returning the foxes to the wild. “I think it will take two years to remove the eagles currently present on the northern Channel Islands, and an additional three years to build the San Miguel Island fox population up, since we’re dealing with so few. We’d like 100–150 foxes on the island.”

Capture of the golden eagles is critical to the long-term success of the island fox recovery plan. The numbers and locations of the eagles are not precisely known. In early August Walton said that there might be “as many as six; I think there may be as few as one.” By late September, however, Coonan could state firmly that the situation was more dire: “Surveys this summer and fall reveal as many as ten golden eagles on Santa Cruz Island alone . . . more than we originally thought.” The birds will be baited with dead cows, in a location away from the foxes, says Walton—”probably on Santa Cruz or Santa Rosa, where access is easy.” They will then be moved to good golden eagle habitat on the mainland, possibly near Reno or Sacramento, or even somewhere in the desert, depending on the season. The eagles will be radiotagged to determine whether they return to the islands. “The chance of successful relocation is high,” says Coonan, “because the eagles on the Channel Islands are likely immature ‘floaters’ less tied to the area than adult breeders would be. Also, as eagle habitat, the Channel Islands probably lack a prey base sufficient to support breeding golden eagles.”

Another long-term goal is to release bald eagles in the islands, although, Walton points out, bureaucracy is a major stumbling block in that effort. “They want to do a big study to see” about the viability of such a reintroduction. In all these efforts, he says, paperwork is a frustrating component, with the need to obtain contracts and permits causing delays even in approved actions like the golden eagle removal.

Coonan, for his part, cited funding frustrations. He has already had to divert monies from other terrestrial monitoring projects—but, as he pointed out, “I couldn’t not”: the island foxes are in danger of extinction, and action is needed now. He has secured emergency Park Service funding for the next three years, at almost $500,000, which will cover the fox sanctuary and captive breeding on San Miguel Island, and eagle relocation. However, the situation on Santa Rosa and Santa Cruz Islands is equally pressing. Santa Rosa, which is 85 percent grassland and provides much less cover than on Santa Cruz, is the “highest priority for new funding.” In addition, the monitoring required for the initial five-year restoration period remains unfunded. At present, Coonan estimates a $1.2 million funding gap.

In light of the serious population declines during the last few years, many biologists think that the island fox should be listed as endangered under the U.S. Endangered Species Act (it has been on the state list since 1971). Coonan says that the U.S. Fish and Wildlife Service is studying the problem, and in his view, listing can come none too soon. “The fact that it’s not listed hurts, both within the agency and without,” insofar as funding is concerned.

Because of the emergency nature and large scope of the actions required, the project cannot be covered solely with federal funds. To help close the gap, the National Park Foundation, the official fund-raiser for the National Park Service, in coordination with the Friends of Channel Island National Park, has established a “Save the Island Fox” program. Information about this program is available at (888) GOPARKS.

The notoriety that comes from an endangered listing will, Coonan suspects, make a big difference in helping the little gray fox escape extinction.

Ironically, on navy-administered San Clemente Island—one of the four southern Channel Islands—in Los Angeles County, a very different situation exists. Here the fox in the henhouse is a fox (like its northern relatives, a unique subspecies found only on one particular island), and the hen is the endangered San Clemente Island loggerhead shrike, one of the rarest birds in North America, with only 13 remaining in the wild. This spring, in an effort to save the bird, Navy biologists trapped and killed 15 foxes that had taken up residence in the birds’ habitat. The bird protection program called for removing and euthanizing up to 50 more foxes this year, but in late May the Navy reversed that decision, opting to trap and hold foxes for a few weeks instead. Jan Larson, the Navy’s regional director of natural resources, said that by midsummer shrike fledglings, both in the wild and in captivity, are learning to fly, so merely keeping the foxes out of the way for a short time should ensure the young birds’ survival. If the foxes had to be held captive for months on end, other foxes could easily move in, making reintroduction more difficult.

Next spring more fox killing might be necessary, though Larson is pinning his hopes on new technology. Currently, a shock-collar system is used to keep the foxes away from shrike nests. When a collared fox crosses a wire encircling the nesting area, a single shock is applied. It has not proved as strong a deterrent as was anticipated, however, so now a new antenna is being tested that would trigger continuous shocks. Experts hope this will prove more successful in diverting the predators from the shrikes.

The San Clemente situation is different from that in the Northern Channel Islands largely in that there are no eagles there, and the populations have been more stable over time—though a new population estimate puts the number of San Clemente foxes at 650 to 750, well below the 1,000 believed to have existed on the island a mere five years ago. Nevertheless, because the northern situation is so dire, some fox defenders plan to petition for the protection of all island fox subspecies under the U.S. Endangered Species Act—the same law that on San Clemente is being used to justify killing foxes to save the shrike.

In a sense, we’re making up the rules and moves of the game as we go along. This is true in all areas of conservation and resource management, of course, but the capacity for a sudden-death finish is far greater on islands, isolated as they are, than on the mainland. Just as in chess, when pieces are under threat or are taken, the value of the remaining pieces is reassessed and strategy revised accordingly. The overall game is the same on the northern islands and on San Clemente Island: to save endangered endemic species. The tactics that biologists and resource managers apply, however, will necessarily be different for the two areas, suited to the immediate balance of power among the players. Island fox or golden eagle? No contest—I’m rooting for the fox. Island fox or loggerhead shrike? In that game, let’s hope we can effect a draw. They’ve both earned the right to long life in their island home.