Wednesday, Oct 24, 2007
One of Americaâs rarest mammals, the endangered island fox, was released from captivity to the wild on Santa Cruz Island on October 8th, marking yet another milestone in the recovery of balance to the island ecosystem. The fox population on Santa Cruz Island has more than tripled since the island fox was listed as an endangered species just three years ago.
Ten island fox pups, all born in captivity this past spring, are being released at two sites within the islandâs central valley. As one of many measures to save the island fox, the captive breeding program is responsible for producing nearly 25 percent of the over 300 foxes now living in the wild on the island, with over 85 pups born in six breeding seasons.
With fox recovery on the rise, the captive breeding program â set up as insurance against the loss of foxes from golden eagle predation â will close this fall on Santa Cruz and San Miguel Islands. The breeding program on Santa Cruz Island was first established in 2002 when biologists discovered that the fox population had declined by over 90 percent and fewer than 100 foxes existed on the island.
âHistorically, fox populations on the island ranged between 1,500 and 3,000,â said Dr. Lotus Vermeer, The Nature Conservancyâs Santa Cruz Island project director. âAfter several successful breeding seasons and with golden eagle predation curtailed weâre optimistic that the foxes will continue this upward trend.â
Golden eagles, a species that never bred historically on the islands, were attracted to the islands by the presence of non-native feral pigs. Golden eagle predation, which placed the fox on the brink of extinction on three of the four northern Channel Islands, has now been nearly eliminated.
âThe stage is set for recovery on the island with a trend of high rates of survival of foxes in the wild, coupled with decreased numbers of golden eagles which feed on foxes, removal of feral pigs, and the return of the bald eagle,â said park superintendent Russell Galipeau.
Bald eagles had disappeared from the islands by the early 1960s, due to human impacts, primarily pollution from DDT contaminants. There are approximately 40 bald eagles reestablished as island residents on the four northern Channel Islands. The first successful hatching in over 50 years of bald eagles on the Channel Islands occurred on Santa Cruz Island the past two spring seasons.
For additional information: www.nature.org/California or http://www.nps.gov/chis/restoringsci/island.html