Island fox recovery program: 2009 annual report

Coonan, Timothy

In 2009 the National Park Service continued to implement recovery actions for endangered island fox subspecies on San Miguel Island (Urocyon littoralis littoralis) and Santa Rosa Island (Urocyon littoralis santarosae). A 10-year program of captive breeding and release of both subspecies had been completed in 2008. The San Miguel captive breeding facility had been closed in 2007, and the Santa Rosa captive facility was closed in 2008 after the final release of captive foxes in November. Island foxes had been removed from the wild for captive breeding on San Miguel in 1999, and on Santa Rosa in 2000. During the 10-year captive breeding program, 138 pups were born in captivity, and 155 foxes were released to the wild, beginning in 2003 on Santa Rosa and 2004 on San Miguel. Excellent reproduction in the wild, exceeding the per capita reproduction in captivity, was the primary reason to cease captive breeding. Also, predation by golden eagles (Aquila chrysaetos) had been almost completely mitigated during the 10-year time period, and wild island fox survival rose to 80–90% on both islands. The excellent survival and reproduction in the wild allowed rapid growth of the small, recovering populations, and by the end of 2009 the San Miguel island fox population estimate was 256 adults and 318 total foxes, and 187 adults and 389 total foxes for Santa Rosa (Figure 1). The park’s island fox program has entered an intensive monitoring phase to insure that recovery continues apace, and to eventually document attainment of criteria which would allow delisting of the two subspecies.

Island fox recovery program: 2009 annual report

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