Channel Island Fox Status Update June 2014

photo courtesy of Dave Graber

photo courtesy of Kevin Schafer

The annual meeting of the Island Fox Conservation Working Group reported that the general status of the six subspecies of Channel Island foxes is GOOD.

All subspecies are maintaining stable populations of over 300 individuals. There are no known specific issues that put any of the Channel Island fox subspecies in eminent threat of extinction. Each island, however, faces its own concerns and challenges. 

  
Island Fox Update 2014 pdf, a specific island-by-island summary

• San Miguel Island - 577 (low of 15 in the year 2000). Population recovered with over 500 individuals since 2010. Concern: New threat from parasites.
• Santa Rosa Island - 894 (low of 15 in the year 2000). Population steadily increasing.
• Santa Cruz Island - 1,085 (low of 62 in the year 2002). Population recovered and stable with over 1,000 individuals since 2009.
• Santa Catalina Island - 1,852 (low of 103 in the year 2000). Population recovered and stable with over 1,000 individuals since 2010. Concern: Climate change impacts and high risk for introduced disease.
• San Clemente Island - 1,002 (not Endangered). Population stable. Concern: New disease threat connected to mineral particulates in the air.
• San Nicolas Island - 350 (not Endangered). Population high, but declining. Concern: Cause of decline currently unknown, see below.

Concerns:

As populations reach the carrying capacity on some islands, there are new challenges to island fox survival. Continued drought appears to be impacting prey and plant species on some islands, which in turn impacts the island fox. Not only are resources reduced, there may be new threats posed by parasites. (Spiny-headed worm on San Miguel Island).

raccoon stowaway on Catalina Express, Dec. 2013
photo courtesy of Ciara Virdan

Introduced disease remains a threat to all island foxes, especially on islands visited by people. Dogs, cats, and introduced species, like raccoons, are all avenues for disease to be transported to isolated and disease-naive island foxes.

 Canine distemper virus (CDV) caused the population collapse of island foxes on Santa Catalina in 1998-2000. Vaccination against CDV is part of protecting island foxes on all six islands. Island foxes, and many other wild species, are unable to withstand the standard CDV vaccine given to dogs and depend on a vaccine produced by Merial, the corporation that makes Frontline and other veterinary products. Unfortunately, there has been no production of the vaccine this year. If the vaccine is not available by fall counting and health checks, island foxes may go unprotected for the 2014-2015 year.

On San Nicholas Island where the fox population has been high and stable for years, annual monitoring has revealed a trend toward decline that is currently unexplained. A group of island foxes on San Nicolas Island will be radio collared in the fall during annual counting to help biologists determine the cause for the decline. (For more specifics see Island Fox Update 2014 pdf above)

Positive Notes:

While there are concerns regarding San Miguel and San Nicolas, island foxes are doing well. Working with U.C. Davis and veterinary pathologists, National Park biologists hope to determine the specific reasons behind the appearance of new parasites on San Miguel Island and the long-term threat they pose to the island fox population.

Monitoring with radio collars on San Nicolas Island will enable biologists to locate individual island foxes that die in a timely manner. Necropsies performed on these animals will help provide information regarding cause of death.

The most positive note of all is that the Island Fox Conservation Recovery Group continues to meet. Nothing is more important for the continued recovery of the island fox than bringing this group of people together who can share their expertise, their experience, and their creative solutions. Friends of the Island Fox thanks all of our donors who made this annual meeting possible!