Breeding Program Offers Hope for Santa Cruz Island’s Vanishing Foxes

Despite efforts to remove the golden eagles that prey on them, fox populations are dwindling so quickly on Santa Cruz Island that scientists probably will have to start a captive breeding program there, experts say.

“Realistically, there’s no way to avoid” captive breeding, said Paul Collins, curator of vertebrate zoology at the Santa Barbara Museum of Natural History. “These are problems that are fixable.”

Forty to 120 foxes inhabit Santa Cruz Island. Scientists already run captive breeding programs on two other Channel Islands, Santa Rosa, which has 32 foxes in captivity, and San Miguel, which has 21.

Scientists have set an October deadline to capture the golden eagles in order to have enough time to set up a facility, organize staff and capture the foxes before breeding season begins in the spring.

It is crucial to capture the eagles soon because “we don’t want to have [the foxes] eaten as fast as we’re putting them out,” Collins said.

Little is known about island fox breeding behavior, and scientists are dealing with some challenges with the captive foxes on the other islands. For example, the San Miguel Island foxes have particularly high rates of parasites, scientists say.

But golden eagles are the most urgent threat.

Scientists began catching the golden eagles two years ago, with the hopes of removing them well before now. But the terrain on Santa Cruz has made the process very difficult, Collins said.

They are currently looking at trapping the six or seven remaining eagles with helicopters and nets.

The 15 or so eagles that have been caught so far have been relocated to northeastern California and Nevada. None has returned to the islands, Collins said.

Until a decade ago, foxes flourished on the island. But golden eagles, drawn by the feral descendants of pigs brought by settlers a century ago, chose the fox as a quick snack and decimated its ranks, scientists say.

Scientists are also working on a program to remove the feral pigs from the island.