Spring Fox Birth Sign of Promise for Recovering Island Ecosystem

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Date: April 3, 2006
Contact: Yvonne Menard, 805-658-5725

The spring season brings promise with one island fox already born on San Miguel Island and births imminent from more than two dozen pregnant females at the captive facilities on the northern Channel Islands. Additional births are anticipated from a significant portion of the 223 foxes living in the wild on San Miguel, Santa Rosa, and Santa Cruz Islands.

In 2005 the wild fox population quadrupled in size on San Miguel Island and doubled on nearby Santa Rosa Island. The wild population on Santa Cruz grew by 30% in each of the past two years. The overall population includes 40 foxes in the wild and 26 in captivity on San Miguel Island, 34 in the wild and 34 in captivity on Santa Rosa Island, and over 150 in the wild and 61 in captivity on the largest Channel Island, Santa Cruz.

These numbers are in dramatic contrast to the populations’ low points between 1999 and 2000 when there were only 14 foxes on San Miguel and 15 on Santa Rosa Islands; all were in captivity. On Santa Cruz Island in 2001 approximately 50 foxes were found in wild.

Moreover, the annual rate of survival of island foxes continues to increase—to 96% on San Miguel, 78% on Santa Rosa (up from 50% in 2004), and 84% on Santa Cruz (up from 60% in 2001). A survival rate of 80% is required for a stable or increasing population.

“We are thrilled to see the island fox population expand with each breeding season,” said Channel Islands National Park Superintendent Russell Galipeau. “The signs are hopeful for restoring viable and self-sustaining wild island fox populations.”

Four of the six subspecies of island fox were added to the federal endangered species list in March 2004 by the U.S. Fish & Wildlife Service with three of these found within Channel Islands National Park.

Since nearly 40 foxes were released last fall on San Miguel and Santa Rosa Islands, seven have died as a result of golden eagle predation. Four golden eagles were captured on the islands this past year and returned to the mainland. Since 1999, 41 golden eagles have been relocated; as few as four golden eagles remain. Biologists are continuing efforts to relocate these last few birds.

Assisting in this process, a bald eagle was recently observed chasing a golden eagle off of Santa Rosa Island near Carrington Point. Today, bald eagles are not an uncommon sight with 25 to 30 resident birds on the northern Channel Islands, a marked increase from their disappearance from the islands in the 1950s due to impacts of the pesticide DDT. Since 2002, 46 bald eagles have been released on Santa Cruz Island as part of the Montrose Settlements Restoration Program study to re-establish bald eagles on the northern Channel Islands.

For the first time in 50 years, a pair of bald eagles has established a nest with two eggs on Santa Cruz Island. Biologists are monitoring the birds daily and hoping for chicks to hatch in the second week of April. 

Signs of recovery from the destructive impacts of feral pigs are evident on Santa Cruz Island with more than 4,800 pigs eliminated since hunting began there in April 2005. Pigs are gone from most of the island, and the large reduction in the pig population may be contributing to the lower number of golden eagles. Pigs were an important part of the diet of golden eagles. The pig eradication project is expected to be completed in June 2007.  

The National Park Service and The Nature Conservancy, along with other partners, are committed to continue efforts to restore the balance of the island ecosystem and preserve the biological richness of the northern Channel Islands for future generations.

Last updated: February 27, 2015

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