Showing posts with label graph of island fox numbers. Show all posts
Showing posts with label graph of island fox numbers. Show all posts

Sunday, June 16, 2013

Good News on Channel Island Fox Recovery

Have you heard the good news? 

All four of the subspecies of endangered Channel Island foxes are doing well. In fact, three of the subspecies are considered to be close to recovered. What constitutes recovery?

  1. Population numbers that have returned to healthy levels
  2. Reduction of threats (those that caused the original near extinction and/or new challenges to survival)
  3. Stability of the first two for at least five years

A graph of the population figures from Santa Cruz and Santa Catalina Islands shows the rapid declines toward extinction in the late 1990s. (Caused by unnatural golden eagle predation on Santa Cruz and introduced distemper virus on Santa Catalina.) 


From 2000 to 2007 island foxes increased in captive breeding facilities on each of the islands and were gradually released into the wild. Once the threats to their survival were reduced, populations of island foxes increased rapidly in the wild. Golden eagles were relocated and bald eagles were reestablished on the northern islands, while vaccinations for distemper and rabies were instituted across the islands.

On both Santa Cruz and Santa Catalina the island fox populations now fluctuate around a number that represents the carrying capacity or maximum population that can survive on each island's resources. The population of any living species alters naturally in response to available food, water and habitat.

The population numbers for island foxes are compiled annually by biologists in the field each autumn. These hard-working people  from across the six islands come together each year in June with veterinarians, scientists and government officials to discuss the status and threats to each of the six subspecies of island fox. We will have more from the annual meeting of the Integrated Island Fox Recovery Team as we compile our notes. It's been a happy busy week.

Sunday, December 16, 2012

Island Fox Populations Recovering

photo courtesy of Kim Michaels, KimMichaels.com
What is the current status of the endangered Channel Island fox? In 2012 the Channel Island fox is robustly heading toward population recovery! Across all islands 90% of the population is surviving on an annual basis.

Every June biologists working with the endangered Channel Island fox come together to share information and update each other on the island foxes populating their island. June Meeting

The general consensus is that endangered populations on San Miguel, Santa Cruz and Santa Catalina Islands are all headed toward or reaching levels of recovery. (Habitat) The Santa Rosa Island fox is now increasing in number, but still is at a much lower population number than before the predation crisis caused by golden eagles and habitat destruction.

Island foxes are counted annually across the California Channel Islands in the late summer and early fall.  Animals are captured in safe traps so they can be given health checks, fitted with radio collars and given vaccinations. Friends of the Island Fox financially supports these conservation efforts.

In 2012 FIF financially supported 14 radio monitoring collars and provided funding for vaccinations against the distemper virus for 450 island foxes.

The official population estimates from 2011 are:

  • San Miguel Island - 581 (up from 15 individuals in 2000)
  • Santa Rosa Island - 449 (up from 15 individuals in 2000)
  • Santa Cruz Island - 1302 (up from ~80 in 2000)
  • Santa Catalina Island - 1542 (up from ~103 in 2000)
  • San Nicolas Island - ~500
  • San Clemente Island - 795
numbers represent the Santa Rosa Island population (pink line)

The recovery of the endangered Channel Island fox is one of the fasted recoveries of an endangered species in North American history. The populations on San Miguel and Santa Catalina Islands have surpassed historically recorded numbers and this year the slight drop in population on Santa Cruz Island was seen as a stabilization of a population that has reached the island’s carrying capacity.

This year the Island Fox Working Group discussed the process for delisting the island fox from the Endangered Species List. Continued monitoring to assure the populations are stable is vital to this process. You can play an important role by helping support island fox monitoring.

Tuesday, November 15, 2011

Island Fox Population Update

courtesy of Anita Machlis
Every year biologists count island foxes across the California Channel Islands in the late summer and early fall. Island foxes are captured in safe traps so they can be given health checks, fitted with radio collars and given vaccinations. When the biologist from the six different islands meet for the annual Island Fox Conference in June, they share their official population numbers and discuss the successes and challenges from each island.


The official population estimates from 2010 are:
  • San Miguel Island - 516
  • Santa Rosa Island - 292
  • Santa Cruz Island - 1302
  • Santa Catalina Island - 1008
  • San Nicolas Island - ~500
  • San Clemente Island - 1127

The numbers show that island fox recovery has been very robust on San Miguel, Santa Cruz and Santa Catalina Islands. The island foxes on Santa Rosa Island are recovering, but at a much slower rate. Each island fox population has its own challenges. For the current status of island foxes by island Download - Island Fox Update 2011 pdf

Stay tuned for updates on 2011 population numbers as they come in from the autumn field counts.