WASHINGTON — To control a bizarre gathering of eagles, pigs and foxes on the California channel islands, federal wildlife officials may have to kill a protected species in order to save an endangered one.

Attracted by a plentiful supply of feral pigs rooting around the islands, a community of golden eagles settled in about 10 years ago to prey on piglets. But they also found that the island foxes, an endangered group of subspecies, also made good meals.

The population of pigs, which reproduce year around, were little affected by the winged predators, but the foxes were decimated.

In less than a decade, wild foxes disappeared from San Miguel and Santa Rosa islands and on Santa Cruz, the population of 1,500 was reduced to just 65.

Fish and Wildlife Service experts are now capturing and removing the pigs and the eagles, but a new study suggests that if the process is not handled properly wild foxes on the islands could disappear forever.

The study, appearing in the journal Science, said that the few remaining eagles will be enough to drive the wild foxes into extinction if all of the pigs are moved first.

"You still have eagles on the islands," said Gary W. Roemer, a New Mexico State University biologist and first author of the study. "If you remove the pigs, you've only got 65 foxes running around that will make those eagles focus more intently on the foxes and drive them to extinction. The most prudent strategy is to get rid of the eagles first and then get rid of the pigs."

Federal officials have been trying. They have captured nearly all of the eagles and moved them to locations on the mainland. But Roemer said there are still nesting pairs of eagles that are too smart or too wary to be captured alive. According to a population project by Roemer and his co-authors, there may be only one grisly option left: killing the protected golden eagles to save the endangered foxes.

"Because eagle eradication is doubtful by translocation alone, other means should be pursued, including lethal removal," the researchers say in Science.

Golden eagles are protected species, but they are not threatened with extinction. The unique island fox subspecies, however, are hanging by a thread, said Roemer.

"The federal officials may have to take a little public heat (for killing the eagles) to preserve an endangered species," he said.

Killing the eagles "is an alternative that we will look into if we have to," said Bridget Fahey, a researcher for the U.S. Fish and Wildlife Service in California.