Golden Eagles Continue to Threaten Island Foxes
Contact: Yvonne Menard, 805-658-5725
Channel Islands National Park Superintendent Russell Galipeau reported today that five of nine Santa Cruz Island foxes released into the wild last November have died, apparently killed by golden eagles.
Golden eagle predation has placed the fox on the brink of extinction on Santa Cruz, Santa Rosa, and San Miguel Islands, and is responsible for a 95% decline in the endemic island fox populations since 1994. For the past four years Channel Islands National Park and The Nature Conservancy have been working together to restore the foxes by creating a captive breeding program and removing golden eagles from the islands.
In late November nine foxes were released from captivity on Santa Cruz Island. The purpose of the release was to examine whether the low abundance of golden eagles currently on the island would allow for safe release of captive-reared individuals to augment the wild fox population. The released foxes, which were monitored with radio collars, died between December 21, 2003 and January 3, 2004.
Biologists captured three of the four remaining released foxes on January 5th and are working to capture the one remaining released fox. No further releases are currently planned on Santa Cruz Island. Additional pens have recently been ordered to allow for expansion of the captive island fox population. There have been no recent deaths in the wild fox population on Santa Cruz, which is estimated to be between 75-100 foxes.
Superintendent Galipeau said, “This is unfortunate news, and indicates that the captive bred foxes on Santa Cruz Island may not survive until golden eagle predation is further reduced. We will continue to work towards reaching our ultimate goal of saving this species from extinction.”
It is estimated that six golden eagles, two pairs and two lone eagles, remain on Santa Cruz. The UC Santa Cruz Predatory Bird Research Group has successfully captured 29 golden eagles on the island and relocated them to northeastern California. The recent loss of foxes on Santa Cruz occurred in spite of a significant reduction in the island golden eagle population.
An outside review of the golden eagle removal program by a panel of eagle experts, coordinated by the Institute for Wildlife Studies, will be conducted later this month. They will be asked to review current methods and strategies and make recommendations to reduce the number of golden eagles.
On neighboring Santa Rosa Island six captive foxes were released in the past two months. These foxes are monitored daily and are doing well. A second release of six additional foxes is scheduled for mid-January. On San Miguel Island the last wild fox was brought into captivity late last year and died on December 31, 2003. There are 38 foxes in captivity, and initial releases to the wild are scheduled to begin in fall 2004.
The National Park Service and The Nature Conservancy are cooperating on a comprehensive program to restore the natural ecosystem on Santa Cruz Island. The program to eliminate feral pigs from Santa Cruz Island is likely to begin late this spring. Feral pigs play a pivotal role in the catastrophic decline of island foxes, by providing a year-round food source for golden eagles, allowing these formerly rare visitors to establish resident populations on the island and also prey on island foxes. Historically, bald eagles occurred in high numbers on all eight of the California Channel Islands. Bald eagles, a federally threatened species, disappeared from the islands due to eating food contaminated with DDT from the ocean. Efforts to re-establish this species will continue this summer when up to twelve juvenile bald eagles will be released on Santa Cruz.
Did You Know?
The endemic island deer mouse is the only native terrestrial mammal common to all the Channel Islands and is larger than mainland deer mice. Densities of deer mice on the islands can be greater than anywhere else in the world. This makes you happy if you're an owl, but not if you're a camper.