Island Foxes Face Off Disease

Tani represents all of the juvenile island foxes that were born this spring (A special Island fox is Born).  As summer turns to autumn these young island foxes will venture off from their parents to begin their own lives. But before they do, they just might have a close encounter of the human kind.

Across the California Channel Islands biologists are catching island foxes in capture cages to count their numbers, replace and outfit radio tracking collars, and conduct annual health checks.

For young island foxes that means a microchip that will identify them for life. It may also mean vaccinations for canine diseases - rabies and distemper. Both of these diseases have a high mortality rate, meaning that most wild island foxes would die if they encountered them. We know this is true because the Santa Catalina Island population of island foxes declined by over 88% between 1998 and 2000 when distemper was introduced to the island. (More about Catalina Island).

Pet dogs and cats that have not been vaccinated can introduce disease to wild populations. Island species like the island fox are especially vulnerable because they have not evolved with the same diseases that animals may be exposed to on the mainland. Wild animals from the mainland can also introduce disease to island populations (see Raccoon on Catalina).

The land managers across the islands hope to vaccinate at least 60-80 island foxes on each island this autumn. The minimum (60 foxes on 6 islands) would be a total of 360 island foxes with a cost of $10 per fox. Just providing minimal disease protection to this endangered species comes with a minimum cost of $3,600. 

You can help provide a young island fox heading out into the world with a better chance of survival by supporting vaccination costs. A donation of $10 will protect an island fox from rabies and distemper. 

You can also make a positive difference by reminding friends and family that vaccinating pet dogs and cats helps protect wild animals. Disease has no sympathy, it can attack an endangered species or a beloved pet. To keep both safe, pets should stay home and leave wild animals to live in their native habitats.


See more of Tani's adventures on Facebook and @ifoxtweet on Twitter.

Microchips for Island Foxes

Biologists capture island foxes annually to count them and to evaluate the health of individuals and the population as a whole. Because not every island fox is captured each year during the annual trapping, those that are caught provide a representative snapshot of the general health of each islands' fox population.

The first time that an island fox experiences an annual health check it receives a microchip so that it will be identifiable as an individual for the rest of its life. The microchip or PIT (passive integrated transponder) tag is inserted under the skin between the shoulders using needle and syringe. When a young island fox, like Tani, receives a microchip it means that the story of her life will be documented from a young age through adulthood. If she is caught again next year, biologists will be able to determine how far she has moved from her parent's territory.


Looking at the data that has been collected on the recapture of island foxes over the years, biologists see a pattern of young male island foxes traveling a great distance from the area where they were born. While female pups tend to stay in areas adjacent to their parents. The first year of an island fox's life can be perilous as they head out on their own into unknown areas.


Microchips also allow the identification of individual island foxes if something happens to them. In the past month, two young island foxes have been hit by cars along roads on Catalina Island. Watch for Foxes.


Radio tracking collars help to monitor the movements and health of island foxes, but not every island fox will receive a $250 radio collar. Every island fox that is captured for the first time during annual counting and health checks does receive an identification microchip. You can help support an island fox Health Check for just $25.


As island foxes continue their successful recovery from near extinction, monitoring their populations takes on greater importance. Through your donation to Friends of the Island Fox you can help support the recovery of the endangered island fox.

How Do You Count Island Foxes?

Across the Channel Islands biologists are setting special enclosure traps to catch island foxes. Each year at the end of summer traps are set-up along specific trails or grids and left open over night. In the evening hours curious or hungry island foxes find their way into the wire mesh traps.

courtesy of Channel Islands National Park

This is how island foxes are counted on each of the Channel Islands. Late summer or early fall is the best season to capture the small foxes because it is late enough in the season that fox pups are no longer nursing and early enough that adult island foxes are not yet preparing to breed for the next batch of offspring.

Before sunrise field biologists head out to check each trap. Frequently if an island fox pup is caught in the cage, biologists report that the parents may be close by, keeping an eye on their youngster. And often island fox parents will leave food, like a dead mouse or two, in front of the cage. This behavior is call "provisioning." Even though the island fox pup is caught in the capture cage, the parents will continue to try and take care of it.

The island fox pup that has been sharing its adventures on Twitter is about to experience an annual Health Check. (See the Twitter box to the right or follow Tani's adventures on FaceBook)


For MORE on an island fox's annual Health Check, LISTEN to biologist Julie King from the Catalina Island Conservancy as she does a health check on an island fox in the wild.

Follow us on @ifoxtweet on Twitter as an island fox pup grows up.