Search This Blog

Loading...

Tuesday, August 12, 2014

Bald Eagle Recovery Spreads Across Channel Islands

Channel Islands National Park reported in July that 60 bald eagles are currently living across California's Channel Islands. In spring 2014 there were sixteen known breeding pairs and fourteen chicks successfully fledged or flew from the nest.

As bald eagles reestablish their population, they help protect island foxes by reducing the probability that golden eagles will colonize the islands. Bald eagles primarily prey on fish and seabirds, while the golden eagles prey specifically on mammals. In the late 1990s, golden eagles nearly caused the extinction of the island fox on three islands: San Miguel, Santa Rosa and Santa Cruz.

Milestone bald eagle birth in 2013.

A landmark this year was the return of bald eagles to San Clemente Island. It is believed this is the first time bald eagles have attempted to nest on this southern island in approximately 50 years. The U.S. Navy manages San Clemente Island and they have been successful in protecting island foxes and other island endemic species. The bald eagles are evidence of recovering habitat on the windswept island. 

The newly established pair was unsuccessful in nesting in 2014, but hopes are high that the pair will find success in the future.

According to the National Park Service the pair of bald eagles combine the successes found on the other Channel Islands. The female was hatched near Juneau, Alaska, in 2004. She was relocated as a juvenile to Santa Cruz Island as part of the efforts to reestablish bald eagles on the National Park islands.

The male eagle is a young adult, hatched in 2007. He began life in an incubator on Santa Catalina Island and was placed in a bald eagle nest on the island, where he was raised by foster eagle parents. 

With a number of active bald eagle nests on Santa Cruz and Santa Catalina Islands, the young pair looked south for territory of their own. Biologists hope that eventually all of the Channel Islands will have resident bald eagles. The recovery of the bald eagle and the island fox is dramatically interconnected. Success for the bald eagles supports island fox recovery and stability.


See Current Island Fox Recovery, island by island.

Tuesday, July 29, 2014

Considering Epidemic Disease Threats to Island Foxes

courtesy of Paul Bronstein
What saved the Catalina Island fox from rapid extinction when canine distemper virus was introduced between 1998-1999? 

An isthmus and human action

Epidemic disease poses a major threat to naive island species like the Channel Island fox. When distemper was introduced via a raccoon transported unknowingly to the island, the disease spread rapidly throughout the island fox population. Nearly all of the 103 surviving Catalina Island foxes lived north of the isthmus, a narrow neck of land connecting the western and eastern parts of the island.


photo from NOAA of Santa Catalina Island
Fox traffic across this exposed area is minimal.

At the recent Island Fox Conservation Working Group Meeting, Brian Hudgens from the Institute for Wildlife Studies (IWS) reported on his findings “Mapping Epidemic Risk in Island Foxes.”

Working with Julie King from the Catalina Island Conservancy, they considered the map of Catalina Island and the areas where epidemic disease is most likely to be introduced via human visitors–the towns of Avalon and Two Harbors, beaches and harbors, and youth camps. They combined this with fox related factors:

  1. island fox population density on Catalina
  2. typical home range size of individual island foxes
  3. range overlap with neighboring island foxes
  4. number of interactions with neighboring foxes
It quickly became apparent that island fox density on Catalina Island is highest in the areas near human habitation; the areas which also pose the greatest risk for disease introduction.

Next, Hudgens created a computer model calculating how introduced canine distemper virus would travel across the island and through the island fox population. What they didn’t expect was that in most cases it didn’t matter where the disease was introduced, in 3 - 4 months an epidemic would cause 100% mortality island-wide. The only deviation was a reduction to 90-100% mortality, if the disease was introduced at the far western end of the island, with the isthmus to hinder the infection spread.


Adding vaccination into the modeling dramatically changed the modeling outcome and the most significant protection was provided by island-wide vaccination of individual island foxes. When a significant number of island foxes across the island were vaccinated in the model, animals that were not vaccinated had a four-times better chance of surviving as well.

Friends of the Island Fox funded 400 island fox distemper vaccinations in 2012.

Each vaccination for rabies or distemper costs $10.
 

Vaccination provides vital protection for these rare island foxes. Successful recovery can only be maintained through vigilant proactive protection.  

Tuesday, July 01, 2014

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!

Wednesday, June 18, 2014

Endangered Island Foxes Stabilizing But Need to Monitor Continues

courtesy of Kevin Schafer
The annual meeting of the Island Fox Conservation Working Group took place yesterday, hosted by Friends of the Island Fox

The good news is that the four endangered populations of island foxes on San Miguel, Santa Rosa, Santa Cruz, and Santa Catalina Islands continue to recover and stabilize. 

Island foxes on the two Navy islands, San Clemente and San Nicolas, are not considered endangered by the U.S. Fish & Wildlife Service (USFWS) and their populations remain stable and at high densities (number of individual animals per square kilometer).

The graph below shows population numbers for San Miguel Island through fall 2013. The population was initially estimated in 1994. Actual individuals were counted when island foxes were in captive breeding pens on the island. Through 2007, the island foxes on San Miguel were gradually returned to the wild. Wild population figures are estimated through an annual catching of individuals and computer extrapolation of that data. More on Counting Island Foxes.


The graph shows how San Miguel's population dropped dramatically due to golden eagle predation at the turn of the century. Fifteen surviving individuals became the founders of the current San Miguel Island fox subspecies; captive breeding by the National Park Service saved this subspecies from extinction.

The population has made an amazing and rapid recovery to a level greater than historically estimated before the crisis. Statistical analysis through fall 2013 calculated that for the fifth year in a row,  individual island foxes on San Miguel have a 90% chance of surviving through the next year and the potential for species extinction is very low.  

Currently the density of island foxes on San Miguel is very high, 10-20 individuals per kilometer in some habitat areas. National Park biologist Tim Coonan believes the data shows the San Miguel Island fox population has fully recovered and has reached the "carrying capacity" for this small island. This means the food and territory resources available on San Miguel can not support continued population increase. The minor population ups and downs since 2010 follow the pattern of a population responding to resource availability. 

Conservation efforts on behalf of the San Miguel Island fox have been very successful. Across Santa Rosa, Santa Cruz and Santa Catalina the stories of population recovery from the brink of extinction are all inspiring.


However, there is an additional cautionary chapter in the San Miguel story. As the island foxes in the National Park have recovered, funding has decreased for their management. The staff that works with the foxes on San Miguel and Santa Rosa has gone from six to three technicians. 

Since the end of 2013 thru May of 2014, seventeen radio-collared island foxes on San Miguel have died from peritonitis caused by a parasitic spiny-headed worm (the exact species is still being determined). This parasite has not been a problem on the Channel Islands before and typically does not cause mortality in canines. The spiny-headed worm is transmitted to the fox through another animal-species host that the fox has eaten.

Today as the biologists, veterinarians, land managers and government officials meet for a second day, they are sharing expertise and ideas about how to respond to this potential threat to the San Miguel Island fox. Over the next few months they will be looking for answers to new questions:
  • What prey species is carrying the parasite?
  • Have island foxes on San Miguel changed to a prey species that is a vector for this parasite?
  • Across San Miguel Island a higher number of island foxes are appearing underweight. Are these foxes infected with the parasite as well?
  • Is drought a factor in this problem?
  • Is high population density a factor?  
  • Why is the number of these parasites so high in individual foxes?
  • During the fall count, there appeared to be a very low number of pups on San Miguel. Is this a natural response to high population density and reduced resources? Is the parasite impacting female health and therefore reproduction?
  • Is the parasite a possible threat to other Channel Island fox subspecies?
Channel Island foxes are rare creatures. Prior to the near extinctions of 2000, little was known about this endemic California species. If there is one thing that has become obvious over the years, it is that change to the island habitat, either directly by people or indirectly through environmental toxins, climate change, or introduced invasive species, island fox survival requires vigilance. 

The continuity of public support and scientific experts engaged in island fox conservation is vital to maintaining this unique species into the future. Funding the Island Fox Conservation Working Group meeting is an important part of island fox conservation.

Stay tuned for more information from the Working Group meeting. 

Monday, June 09, 2014

Annual Meeting of Island Fox Conservation Working Group

photo courtesy of Channel Islands National Park
 Every year biologists, veterinarians, researchers, educators, private individuals, government officials and land managers involved with Channel Island foxes meet in June to share information. As the four endangered subspecies have approached population recovery, funding for this important annual meeting has weakened. 

This year the June 2014 meeting of 
the Island Fox Conservation Working Group 
is being hosted by Friends of the Island Fox!

Through the generous donations of private individuals and community organizations, FIF is making sure this important networking and sharing of scientific information continues. Thank you to all of our island fox supporters. You have made a huge difference for the continued success of endangered island fox recovery.

When the Working Group meets next week there will be specific updates on each island fox subspecies. (Six different subspecies). 

Representatives from Channel Islands National Park, the U.S. Fish & Wildlife Service (USFWS), Institute for Wildlife Studies, Catalina Island Conservancy, United States Navy, The Nature Conservancy, University of California at Davis School of Veterinary Medicine, Santa Barbara Zoo, Smithsonian Institute, Channel Islands Park Foundation and Friends of the Island Fox will present reports and discuss issues pertaining to island foxes.

Island fox having teeth checked during Health Check, NPS
Some of the Report Topics:

Proposed Issues for Discussion:

You can see the important items that will be addressed and information that will be shared. The greatest successes for endangered species come when people sit down together and share their expertise and ideas for solutions. 

Thank you again to all of our island fox friends that helped to continue this important meeting.

Tuesday, June 03, 2014

Let's Go FOXES!

The Fort Collins, Colorado, Foxes are celebrating endangered island foxes for the third year in a row. 

The Foxes are part of a summer Mountain Collegiate Baseball League and again this year they will help raise funds for island fox conservation at one of their home games. 

The Fort Collins Foxes meet the Winsor Beavers
on Sunday, June 8th in Fort Collins, CO

The team will raffle off a replica Major League jersey to raise funds to help support Channel Island foxes.


Fort Collins has a second connection to island foxes. Colorado State University at Fort Collins maintains physical scat and blood samples of island foxes from Santa Cruz Island. These specimens are important to biologists and researchers working on issues concerning island foxes.

If you can't attend Saturday's game you can still support foxes by wearing one of the many styles of Foxes' baseball caps. When you purchase a Foxes baseball cap on-line, the team will make a 15% donation to Friends of the Island Fox

GO Foxes!

Saturday, May 24, 2014

Students Helping Endangered Island Fox

Summer is a great time to visit the Channel Islands and the endangered island fox.

Island Fox Ambassadors from Carpinteria Family School
It is also a great time to contribute to island fox conservation. The students of Jan Silk's class at the Carpinteria Family School are Island Fox Ambassadors. Not only have they raised funds for island fox health checks, they participated in an additional service-learning project while visiting Santa Cruz Island in Channel Islands National Park.

During the years that Santa Cruz Island was a ranch, not only were large domestic livestock introduced to the island, so were invasive non-native plants. While the goats, pigs and sheep have been removed from Santa Cruz, the fennel and non-native grasses persist. Non-native plants typically do not provide food for wildlife and can push out the native plants. 

The students helped remove invasive fennel.


Trash left behind by visitors and campers can also be hazardous to native animals like the endangered island fox. The students gathered up any trash items they found and packed them off the island.

The students of Carpinteria Family School have shared their hearts with the endangered island fox and discovered not only California's Channel Islands but the role they can play as individuals and as a group in making a positive difference.

natural rocks on the beach on Santa Cruz Island

Friends of the Island Fox works with teachers, schools, youth groups and community organizations to build connections between people and the wildlife of the Channel Islands. 


For more on school programs and community presentations.

FIF school presentations are fully booked through June. We will begin scheduling for the next school year in Sept. To receive an e-mail regarding the schedule in 2014/15, e-mail islandfoxnews@gmail.com

Tuesday, May 06, 2014

Visiting The Channel Island Fox

Santa Cruz Island fox (Urocyon littoralis santacruzae)
Summer is a great time to visit California's Channel Island fox.

May 3, 2014 - Friends of the Island Fox led a trip to Scorpion Anchorage on Santa Cruz Island in Channel Islands National Park

The day began with a visit to the National Park Headquarters in Ventura and a tour of the Visitor Center.  As well as the island fox, Santa Cruz is home to numerous endemic plants and animals (species found only on the Channel Islands, like the island scrub jay)
 
Channel Islands National Park Visitor Center
Much of the water surrounding the Channel Islands is also protected by the Channel Islands Marine Sanctuary. Kelp forests surrounding the islands provide food and shelter for a variety of marine species. Ranger Tina provided an in depth talk on tide pool creatures.

The island received six inches of rain in early April which helped to make the island green and the wildflowers bountiful.


Island foxes were also abundant. Our first island fox of the day was spotted within minutes of arriving on the island. Over the course of the day, groups saw up to 10 individual island foxes. 

 
Video courtesy of trip participant Douglas E. Welch - see more trip photos at WelchWrite.com

This trip we observed interesting interactions between island foxes:

One older individual, climbing up the hillside leaving the campground, area became alert and defensive when another fox began following it. The older fox arched its tail, making itself appear larger, and defensively turned around to face its follower. However the island fox following the older individual was smaller and appeared younger, more spry. When the smaller fox reached the defensive fox, it immediately displayed submissive behavior–licking under the chin of the older fox. The older fox relaxed. There seemed to be recognition between the two individuals. It looked somewhat like a pup with a parent, but both of these island foxes were definitely adults. It is possible that the smaller fox was either an adult offspring from another year or a female approaching a male, not her mate. The two island foxes walked side-by-side for a couple of yards along the hillside. (see video above) Then the older fox continued on its way out of the campground area. The younger fox, turned around and back tracked along the path she had just walked and went the other direction. 

In another situation, two healthy adult island foxes coming from opposite directions toward the stream bed at the edge of the campground, specifically avoided each other. They passed within ten feet of each other and actively avoided an encounter. One of these island foxes was wearing a radio collar.

Seeing multiple encounters between individuals is an exciting demonstration of the successful return of this endangered species.  (More about island foxes)


Scorpion Anchorage, Santa Cruz Island, Channel Islands National Park
You can visit three of the islands where island foxes live: Santa Cruz and Santa Rosa Islands, in the Channel Islands National Park, and Santa Catalina Island. Each island has its own unique traits and treasures, but they all have Channel Island foxes.

courtesy of Kevin Pease
Island foxes have a long relationship with humans. We can all help that relationship continue long into the future by participating in conservation efforts to protect this species and by respecting these wild animals when we visit their only home in the whole world. 




Monday, April 14, 2014

The Science of Counting Island Foxes

courtesy of National Park Service
In 2000 when there were only 15 island foxes surviving in captive breeding pens on San Miguel, you could count them easily on your fingers.

Today all Channel Island foxes across the six islands where they live are back in the wild. (A few rescued individuals from San Clemente Island can be seen in mainland zoos.) The recovery of the endangered island fox on San Miguel, Santa Rosa, Santa Cruz and Santa Catalina Islands has been record-breaking and the days of counting all of the physical island foxes are long gone.
 

courtesy of National Park Service

The process of counting foxes on each island begins in the fall with special capture cages.

These cages are set up either at the cross sections of grids or along a string depending on the island and its topography (More on strings and grids)


Cages in an area are set out over the course of a specific number of nights and checked each morning. On Catalina, each string is run for four consecutive nights; after that, typically the majority of individuals would be foxes that had already been captured on previous nights. Each island fox is identifiable because it has a Passive Identification Transponder (PIT) microchip. An island fox caught for the first time receives a PIT tag. From that point on the PIT tag allows it to be recognized as a specific individual. It can take weeks for biologists to evaluate each island.

Over the course of all the capture nights, the number of individual island foxes, their gender, ages and location caught are documented. Island foxes are quite territorial, therefore it is unlikely that a fox caught in one area of the island would be found on a different area of the island during the month of counting. (If it is, that is important too.)

The data is input into a modeling program for analysis. Different programs may be used on different islands and over the years land managers may change which program they use. The modeling program calculates the density of island foxes in specific habitats across the island and estimates a total island population.

Sometimes, however, it takes a human brain to see complexity in the numbers. On two islands where recovery has been robust over the past few years, San Miguel and Santa Catalina, the estimated population numbers appear to be higher in 2013 than they were in 2012.





But observations on both islands conclude that drought may have reduced births and did cause starvation in a number of pups last summer, prior to counting. How could the population number increase while the number of surviving pups decreased significantly?

Biologists Calvin Duncan and Julie King from the Catalina Island Conservancy explain that on Catalina they caught a greater number of adult island foxes that had not been counted for a number of years. Young animals are more likely to be curious and challenged with finding food; they venture into capture cages more readily. Once an animal is in the cage, no other can be caught that night. This year, on the fourth night of capturing, they were still finding a high percentage of animals that had not been caught on previous nights.

courtesy of Kevin Schafer

The increase in the population number for Catalina is warranted because of the number of unique individual animals that were counted. But rather than an increase in the population, the number represents a refinement of the estimate toward greater accuracy.

On both San Miguel and Santa Catalina Islands, island fox numbers have surpassed historic population figures. Both islands may have reached carrying capacity, or the number of individual animals that can find the territory and food resources necessary for a healthy life. As the drought continues this summer, there may be further impacts not only on pups, but also on older individuals.

Counting island foxes provides an important picture of island fox recovery, but observations throughout the year, health checks, blood tests, data collected from radio-collared island foxes and necropsies is vitally important to understanding the whole recovery picture.

Tuesday, April 08, 2014

Studying Island Fox Blood

What is the biologist doing to that island fox?


Blood samples play an important role in not only monitoring island fox health, but also in alerting biologists to potential diseases island foxes may have been exposed to. When an animal comes in contact with a disease, their immune system creates antibodies to fight against the disease threat. 

By testing island fox blood samples for titers, levels of antibodies, biologist can determine if island foxes have encountered new disease threats. They also can tell if individuals are carrying antibodies from vaccinations at high enough levels to protect them against know diseases like rabies and distemper.  

Serology, studying blood samples, may not sound very exciting, but it is very important to the recovery of the endangered island fox. Thanks to a $2,000 grant from our friends at the Fresno Chaffee Zoo, island fox blood samples taken during annual fall health checks last fall will be examined for antibodies to various canine diseases (distemper, parvo, etc.).