Prolific piglet production means a steady food source the golden eagle. The raptors enjoy a year-round diet of piglets, but also prey on foxes.
The island was once inhabited by bald eagles that fed on fish and carrion but not foxes. The presence of bald eagles likely prevented golden eagles from establishing themselves.
"The fox evolved for thousands of years when they had no aerial predator," Menard, the Channel Islands National Park staffer, said.
But bald eagles disappeared from the islands during the 1960s. The Park Service and Nature Conservancy place the blame on the pesticide DDT, which people dumped off the southern California coast.
In succeeding decades, protection programs have boosted golden eagle populations on the mainland. The raptors have now colonized Santa Cruz because of the piglet food source, according to Nature Conservancy and Park Service staff.
Fox Decline
The eagles' arrival precipitated a drastic decline in fox populations. In 1993 there were about 1,500 foxes on Santa Cruz. Eight years later the number had fallen below a hundred.
An ongoing bald eagle reintroduction program on the island, along with the elimination of feral pigs, is expected to prod the golden eagles to seek alternative nesting grounds.
Golden eagles are also being relocated to the mainland, an option not available for wild pigs, which the state designates as pests.
The concerted actions may come none too soon for island foxes, whose numbers have declined to the point where captive breeding is necessary.
To date, about two dozen captive-reared foxes have been successfully reintroduced to the wild.
"Massacre" Protested
Scarlet Newton is a spokesperson for the Channel Islands Animal Protection Association (CHIAPA), based in Santa Barbara, California. She believes the Santa Cruz's wild pigs have been sentenced to death under false pretenses. She said that she hopes to stop what she terms a "massacre."
CHIAPA maintains that the pigs' ground-churning habits constitute a restorative ecological benefit to Santa Cruz. The group also contends that pigs and foxes coexisted on the island for several centuries before the National Park Service began managing the island.
While entreaties to stop the pig hunt have thus far met with little response, CHIAPA said it is not giving up on its efforts to save the pigs.
"We're working from every possible angle," Newton said. "We have people looking at the situation from a legal angle. We're begging federal elected officials to please halt this project, and we're mustering public outcry to hopefully encourage those elected officials to step up to the plate."
For other non-native Channel Islands animals, such efforts come too late. In the 1980s the Nature Conservancy eliminated feral sheep from the island. A decade ago pigs were removed from Santa Rosa island. Meanwhile, other islands have been rid of non-native burros, rabbits, and rats.
Similar efforts have been carried out elsewhere in world, including the Pacific's Galapagos Islands.
Menard, the Channel Islands National Park staffer, said, "It's all been done to remove introduced species that are disrupting the natural balance of the island ecosystem."
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