Evading extinction: The recovery of island foxes on California’s Channel Islands

April 7, 2016

Efforts of multiple partners under the ESA lead to fastest ever recovery of a mammal in the United States

Island foxes on Santa Cruz Island. Courtesy photo by Chuck Graham.

“In light of the environmental challenges we face today and we see on the horizon, we celebrate victories and steps forward to conserve and protect the unique natural resources of southern California.” 
– Steve Henry, Field Supervisor, Ventura Fish and Wildlife Office

Photo Credit: USFWS

The island fox is known and loved as an iconic symbol of California’s Channel Islands ecosystem. But in our recent history, island fox subspecies endemic to four of the islands were faced with the very real and very daunting fate of extinction. In the late 1990s, their populations on San Miguel, Santa Rosa, Santa Cruz and Santa Catalina Islands plummeted by 90 percent to near-catastrophic levels. By the turn of the century, extinction was imminent.

Their declines were due primarily to predation by golden eagles on the northern Channel Islands and a canine distemper disease outbreak on Santa Catalina Island. On Santa Rosa Island, the island fox population dropped from 1,708 in 1994 to only 15 just a few years later. Island fox numbers on Santa Cruz and Santa Rosa Islands dropped from more than 1,400 to 55 and 450 to 15, respectively. Around the same timeframe, the Santa Catalina population dwindled to around 100.

On March 5, 2004, the U.S. Fish and Wildlife Service (Service) listed four of the six island fox subspecies as federally endangered under the Endangered Species Act (ESA). To halt the downward spiral of island fox populations, the Service and land management partners from the National Park Service, The Nature Conservancy, and Catalina Island Conservancy took immediate action to eliminate or greatly reduce the primary threats facing the subspecies, namely predation, disease and low population numbers.

Non-native golden eagles were non-lethally relocated and their prey-base was removed from the northern Channel Islands, providing opportunity for bald eagles to reestablish to their historic territories on the Channel Islands. Island foxes were vaccinated against canine distemper to guard against disease outbreaks, and a captive breeding program was established. Island fox populations were closely monitored throughout the recovery effort. Now, less than two decades later, Channel Island fox populations on the northern Channel Islands are thriving, and the Catalina subspecies continues to improve.

Photo: USFWS

“The remarkable recovery efforts of land managers and conservation partners over the past two decades on behalf of the Channel Island fox is the reason for this historic recovery success,” said Service Director Dan Ashe. “The speed at which these subspecies have recovered points to the strength of the ESA in focusing conservation attention and catalyzing recovery actions, and demonstrates what we can achieve together.”

Table: Conmparison of estimated number of wild
adult and juvenile island foxes for each listed
subspecies from 1999 with 2014. Source:Recovery
Plan for Four Subspecies of Island Fox (2015)

Representing the fastest successful recovery for any ESA-listed mammal in the United States, the Service announced in February 2016 a proposal to remove San Miguel, Santa Rosa and Santa Cruz Island fox subspecies from the Federal List of Threatened and Endangered Wildlife which would be an historic success for the multiple partners involved in recovery efforts.

Channel Islands National Park Superintendent Russell Galipeau said, “It is rewarding to know that the dedication of so many scientists, veterinarians, and community members has been instrumental in saving this endangered species.”

Channel Islands National Park Superintendent Russell Galipeau said, “It is rewarding to know that the dedication of so many scientists, veterinarians, and community members has been instrumental in saving this endangered species.”

While data suggest island fox populations on Santa Catalina have also increased to historic levels, the potential for a disease outbreak remains an existing threat. Therefore, the Service recommended the subspecies’ status be reclassified from endangered to threatened, thus retaining ESA protections.

The Service collaborated with land managers of the Channel Islands including the National Park Service and The Nature Conservancy, as well as a team of stakeholders including scientific experts from academia, state and local governments, private, and non-profit organizations, including the Friends of the Island Fox and the Institute for Wildlife Studies, to identify and ameliorate threats to the island fox.

“This is not only a story of recovery, but a story of the power of a dedicated team of conservationists, biologists and scientists,” said Robert McMorran, fish and wildlife biologist with the Ventura Fish and Wildlife Office. “With the unwavering dedication of our partners, near tragedy has become a true recovery success story for the island fox.”

See the full announcement and other associated information at the links below:

News release and associated documents

Recovery Plan