Land of the Vanishing Foxes - helping the San Miguel Island foxes survive

Animals, Jan, 2000 by Deborah Knight

In the past, bald eagles nested on the islands and would have fended off golden-eagle incursions. Since bald eagles eat primarily fish, they never presented a threat to the foxes. But bald eagles had vanished from the islands by the 1950s, dealt a deathblow by DDT. The islands had also been grazed since the 1800s. On San Miguel, thousands of sheep sheared the land of native shrubs and trees. Much of the island is now covered with normative grasses and, in some areas, little but sand.

Unaccustomed to death coming from the air and with little cover, the island foxes make easy pickings. In April 1999 the national park convened a team of experts, among them Roemer, to draw up a recovery plan. The team recommended an ecosystem overhaul: live trapping and removal of the golden eagles, elimination of the feral pigs, restoration of native vegetation, and reintroduction of bald eagles. The plan would take several years to complete. The pigs carry pseudorabies--a virus that can be deadly to other animals--so they could not be brought to the mainland. They would have to be hunted or trapped. The recovery team also called for immediate steps to save the remaining foxes: capturing all the foxes on two of the islands and a monitoring program on the third. The captured foxes were to be held in "sanctuary" pens and captive-bred until it was safe to release them.

To Roemer's dismay, the National Park Service funded only the work on San Miguel. With foxes also vanishing on the other two islands, according to Roemer, "these guys could go extinct right under their noses."

Each day Rutz and his assistant check and rebait dozens of small wire traps. They replenish the bait can, sometimes with an experimental new offering, such as a cooked chicken gizzard. In the wild, island foxes eat fruits and berries, insects, mice, and small birds. Rutz has tried almost everything to lure them into the traps: bananas, different kinds of fish, every part of a chicken, frozen quail, pasta sauce, barbecued beef, and scent attractants that range from sweet to stink to female-in-heat urine scent. "A lot of times," he says, "you're at the grocery store and you're walking down the aisle, and you think, Ho, I wonder if they'd like this."

They set the can in the back of the trap just behind a treadle that, when stepped on, snaps the door closed. With a twig, they dip into a jar labeled "Baits and Lures," filled with loganberry jam or some other commercial attractant, and daub it on nearby bushes and at the entrance to the trap. In two months they have caught 12 foxes. These unwary foxes came easily. But the trap-shy foxes frustrate Rutz; he knows he is in a race against time to save the animals. "You see their footprints walk up to your trap and walk by," he laments.

During the summer of 1999 there were no more suspected golden-eagle deaths, but it was feared the birds would return in the fall, when immature eagles normally disperse. Sure enough, in mid-October, Rutz had a mortality signal. It came from a male Rutz had been trying to trap for weeks, one he had followed during his telemetry studies. The remains lay sprawled out on the side of a hill, eaten in the familiar raptor pattern. With only four males in captivity, the loss was a blow. "He represented 20 percent of my known male breeding population on this island," Rutz explained. "Also, having seen him in the field, putting a collar on him, tracking him, seeing him play with a pup one day ... you get attached to these guys."