Friday, January 21, 2022

Friends of the Island Fox is Now a Partner with 1% for the Planet


Friends of the Island Fox is pleased to announce that we have joined 1% for the Planet as a nonprofit partner! This partnership is intended to advance our impact on the Channel Islands as well as involve more businesses and individuals in the environmental movement.

1% for the Planet is committed to building support for the essential work of Friends of the Island Fox and other nonprofit partners within six core issue areas: climate, food, land, pollution, water and wildlife. 1% for the Planet approved nonprofit partners are carefully vetted environmental organizations that are eligible to receive certifiable funding from their members.


"The intent of 1% for the Planet is to help fund these diverse environmental organizations so that collectively they can be a more powerful source in solving the world's problems," writes Yvon Chouinard, co-founder of 1% for the Planet.

More about 1% for the Planet

Learn more by viewing Friends of the Island Fox's profile here: Friends of the Island Fox - 1% for the Planet

Tuesday, December 28, 2021

Not Every Fox on an Island is an Island Fox

Friends of the Island Fox educators had a great question from a student in the Oak Park School District in California.

Are the foxes on the San Juan Islands in Washington island foxes?

Monascherie for San Juan Visitors Bureau

San Juan Island in Washington does in deed have a fox population; it's the only island along the coast of Washington that does.

The foxes range in color from tawny red to silvery black, but if you know your foxes there is a distinct characteristic that tells you these foxes are very different from the Channel Island fox. The tail tip is white! 

How to ID North American Foxes

The foxes on San Juan Island are red foxes (Vulpes vulpes). 

The story of the San Juan Island foxes has some similar plot points to island foxes

  • introduction of non-native species to an island
  • damage to an island ecosystem
  • a search for ecosystem balance

In the 1800s, a lighthouse was built on San Juan Island to help ships avoid dangerous waters. (Just like the lighthouse on Anacapa Island). Transporting fresh food to the island was costly, so in the late 1800s, European rabbits were introduced to San Juan Island to provide a fresh meat source for lighthouse keepers.

Without any natural predators on the island, the rabbits quickly began devouring the native island plants. The island ecosystem was crashing. There were too many rabbits for the people to control. It's believed that some time around 1930, red foxes and/or red foxes bred to have black fur for the fur industry were introduced or set free on San Juan Island. It was hoped that the red foxes would control the rabbit population and also provide foxes for people to hunt.

The red fox population on San Juan Island is fairly small, but they have controlled the European rabbits and, fortunately, they have not had a negative impact on other native island species. The island has returned to a tenuous balance and the red foxes are now protected on San Juan Island. 

The red foxes have been isolated on San Juan Island for almost 100 years. 

Will they develop island adaptations? Will they become island dwarfs over time like the island fox? How long will it take for them to evolve into a new species? Only time and evolution can tell.

Island foxes on California's Channel Island remain the only island-endemic fox species in the United States.

If you have a good question about island foxes send FIF an email at

Tuesday, December 21, 2021

Island Fox Microbiome at the Smithsonian!

FIF's 2020 Research Grant recipient Dr. Alexandra DeCandia recently spoke about her work investigating the island fox microbiome

Watch the video of the program

Here's a behind the scenes look at her process extracting the DNA of different microbes from the island fox swab samples.

Dr. Allie reports: 

I inventoried over 800 swabs and over 300 blood samples collected from Channel Island foxes and island spotted skunks in 2020. I then extracted DNA and prepared samples for microbiome sequencing (a process called "library preparation"). The last step of the library preparation is cleaning the library–in essence, removing all of the DNA fragments that I don't want to ultimately sequence.

Although it may seem like a straightforward process, this took a bit of troubleshooting. After a few failed attempts, I worked with the lab manager at the Smithsonian National Zoo's Center for Conservation Genomics to learn how to run an "eGel". In this approach, you put your library in an agarose gel (which looks like a think rectangle of gelatin), run an electrical current through the gel to separate DNA fragments based on size...

(under UV light, the fragments look like glowing bands of the gel), and then pull out the band you want to sequence (in my case, fragments roughly 400 base pairs in length).

Then the DNA had to be treated to remove "gel particles and other potential contaminants."

Overall, this was a nerve-wracking process, but thankfully it worked!

Dr. Allie has submitted all seven sequencing libraries to the Princeton University Genomics Core Facility for sequencing. She reported on some preliminary findings during her "Date with a Fox" presentation. This is Fox Science at work! 

Your donations support this cutting-edge science that will provide important information regarding island fox health.  

Swab collection continues.

What is a microbiome? and Why is this important for island foxes?

Wednesday, December 15, 2021

A San Miguel Island Fox Gets A Radio Tracking Collar

San Miguel Island is a windswept, treeless place. The most northwest of the California Channel Islands, and part of Channel Islands National Park, few people visit, but this island provides vital habitat for the rare San Miguel Island fox.

This fall during fox counting, a young male island fox was captured in this area of dunes and sage. Few pups were captured in 2021 on any of the Channel Islands; continued drought conditions reduced available food resources resulting in fewer pups being born. 

Male M515 is one of the few island fox pups documented in 2021. Following his health check, he was fitted with a radio-tracking collar funded by Friends of the Island Fox. This radio collar will enable biologists to monitor his survival and track his movement. 

As a young adult, M515 has yet to establish his territory. Will he stay in this dune area or roam to more shrubby parts of the island?

Will he stay close to the coastline or will he find a home in the island's interior? Which area will provide the greatest quantity and quality of resources? How large of a territory will he patrol? These are important questions that researchers are trying to answer.

Young male island foxes are on the move in autumn and winter. Is his priority finding a territory or a mate? We don't really know. As a youngster, however, he will have competition for territory from other males. The population of island foxes on San Miguel Island was estimated at 277 individuals in 2020. (2021 population estimates are currently being calculated.) Because the current population is down from an estimated high of 453 in 2019 (an average rainfall year), M515 may have an easier time finding a territory of his own.

His island is a beautiful, if rugged place to live. If he's lucky, winter rains will bring renewed plant growth and prey species. He might find a mate and father pups before his first birthday in April.

Through it all, his radio collar will allow biologists to track his survival and see where he ends up on the island. If you donated to Friends of the Island Fox - M515 might be wearing a collar you helped provide! 

Every Donation Helps Island Foxes

More about San Miguel Island

Friday, December 10, 2021

Fox Foto Friday - This Is Island Fox Science

Fresh from the fox swabs...This past week, Friends of the Island Fox had the opportunity to spend some time in the field with the biologists of the Catalina Island Conservancy during their final days this season counting and providing island foxes with health checks.

During health checks, samples, like the one shown above, were taken. (how are island foxes swabbed?)

Soon these swabs will be boxed up and sent across the country to enrich the data set of Dr. Alexandra De Candia. During FIF's first virtual "Date with a Fox," Dr. Allie shared her work on the island fox microbiome and its importance for fox health and immunity.

Dr. Allie explains that Catalina Island biologists "have been collecting swabs since 2017, so we are building a really nice longitudinal dataset. 2020–2021 samples will help that dataset grow. This will allow us to look at changes in fox microbiomes through time and (once we have enough repeat individuals sampled) see how treatment or past history of mite infection alters microbiomes in the short- and long-term."

If you missed the virtual event you can watch the video here.

More on the connection between microbiome and fox health on Catalina Island.

Not only were the CIC biologists taking these samples to enrich the microbiome data set, they were also putting radio collars, funded by you, on island foxes.

Wednesday, December 01, 2021

Friends of the Island Fox Wants to Give Back to You

 It's Giving Back Wednesday!

Thank you for your support of island fox conservation.

If you missed FIF's first virtual program, you can now watch a video recording. 

"Date with a Fox" Nov. 20, 2021: Dr. Alexandra DeCandia provides an update on her island fox microbiome research, supported by your donations, and island biologist Lara Brenner outlines a new effort to protect island foxes from introduced species on Santa Cruz Island.


We hope you'll share this with your friends.

Stay updated about future "Date with a Fox" live virtual programs by signing up for FIF's newsletter

Friday, November 19, 2021

FIF Research Grant to Investigate Island Fox Territory Size

Friends of the Island Fox is happy to announce Kathleen "Katie" Elder is the recipient of the FIF 2021 Island Fox Research Grant. 

island fox with GPS collar
In conjunction with the Biological Sciences Department of California Polytechnic University (CA Poly), San Luis Obispo, and Channel Islands National Park, Elder will be investigating territory size for individual male island foxes on Santa Rosa Island. This project will replicate and expand on a Santa Rosa study done in 2009–2010 using specially adapted GPS radio-tracking collars. Twelve years ago, Santa Rosa Island foxes were just starting to recover, with an estimated population size of 389 individuals. The GPS-collared male island foxes were calculated to have a territory size on Santa Rosa of 3.39 square kilometers (Drake et al. 2015).

Two island fox populations, which have not encountered recent population declines–San Nicolas and San Clemente Islands–have been found to have vastly different territorial sizes: 

  • San Nicolas Island (2005–2006) 1.81 square kilometers (Powers 2009)
  • San Clemente (2010–2011) .42 square kilometers (Sanchez 2012)

In the fall of 2020, Santa Rosa Island was home to an estimated 2,657 island foxes. As the population has recovered fully, have territory sizes decreased? 

island fox on Santa Rosa Island, courtesy Tim Bean

Elder will be investigating whether the density of the island fox population impacts territory size and/or the extent of fox territory overlap. She'll also be looking at whether habitat quality is a factor in territory size or territory use during different parts of the day. Are there some habitat areas, like beaches, that are included in the territory of multiple foxes? How do these territorial animals manage areas of overlap? Do they access overlapping areas at different times of the day? Are individuals with inland territories venturing to beaches occasionally? Beach areas provide supplemental food resources, but also may be primary zones for contact with introduced species and disease vectors.

Understanding territory size, overlap, and use, impacts island fox management. Territory-size data plays a role in the algorithms for calculating overall island population estimates. If the data on territory size is outdated, population estimates could be over- or understated. If specific habitats or areas are more important to island fox success, identifying those areas will help secure targeted protections. Identifying areas where island foxes are more likely to encounter threats, may also help us find ways to reduce those negative impacts.

If you are an FIF donor, 

you are making this important work possible.


If you haven't donated yet, Please Donate 

It's Science, For Fox Sake!


More about FIF funded Research 


Drake, E.M., B.L. Cypher, K. Ralls, J. D. Perrine, R. White, and T. J. Coonan.  2015. The Southwestern Naturalist. 60:247-255

 Sanchez, J. N. 2012. Spatial ecology of disease spread in the island fox. M.S. thesis, Humboldt State University, Arcata, California.

Friday, November 12, 2021

Fox Foto Friday - Color-Coded Radio Collars

Why so many smiling faces? 

Nineteen refurbished radio-tracking collars and two new ones provided by Friends of the Island Fox are being deployed onto Catalina Island foxes, right now.

Why the bands of color?

Catalina Island Conservancy biologist Emily Hamblen explains that the color-coding is individual to each collared fox. Especially on Catalina Island, this adds an additional way to collect information on individual animals. "When visitors report that they have seen a fox with a specific color combination," Hamblen says, " helps us keep track of foxes between telemetry shifts."  

This fall on Catalina Island, four new faces are working with Hamblen: (Above, from left to right) Makenzie Henk (Conservancy wildlife biologist), wildlife interns Ava Johnson and Jenna Hatfield, and Ricky Robbins (wildlife technician). Hamblen says: "This year, the fox interns helped us prepare the collars by adding the colored tape, checking to ensure the frequencies were correct, and punching holes in the leather of the collars so that we can place them on foxes more quickly in the field."

The Catalina team is into its third week of counting island foxes and placing radio collars. "We have placed 11 collars so far," Hamblen reports, "and plan on placing the rest over the next 4 weeks!" 

She added, "I was reflecting on how important the contributions of FIF have been to the success of this year's fox program."

In 2021, your donations provided the following for island foxes on Catalina:

Your donations to Friends of the Island Fox makes a difference and goes directly toward conservation and research efforts.

Which radio collar on the table, did you help fund?


Watch a radio-collared island fox being released

2021 Radio Collars for Channel Islands National Park

Thursday, October 28, 2021

Fox Foto Friday - Do Foxes Have Vampire Teeth?


island fox skull

Check out those teeth! Do island foxes have vampire fangs?

Close-up of island fox canine teeth
No. Those pointed fangs on either side of the incisors are called "canine teeth." There is a matching, though smaller, elongated pair of canine teeth on the lower jaw. 

Whether they are on an island fox, a baboon, a horse, or a jaguar, they're still called "canine teeth." Most likely, people first noticed these elongated teeth on dogs and then realized that most mammals have the same tooth structures.

Typical Halloween vampires have enlarged canine fangs. A real vampire bat has canine teeth, but it actually bites with its sharp incisors–the two front teeth.

Canine teeth are typically the longest teeth in a mammal's mouth. For island foxes and all of their dog and cat family relatives, the canine teeth help to grab hold of prey. 

Teeth can record data about an individual animal and the enlarged size of the canine tooth makes it important for science. See research with fox teeth

You have canine teeth, too. Your upper canines are the two longest teeth in your mouth and on some people they are naturally more pointed. People use their canine teeth for tearing food. Your dentist might also refer to these teeth as "cuspids" or "eyeteeth," because in humans they align with the eye.

Skulls and fangs can seem spooky at Halloween, but they're also a fascinating part of science. 

Tuesday, October 19, 2021

Estimating Island Fox Age Using Cementum Rings In Teeth

Slides of tooth specimens - S. Baker

In October 2019, Friends of the Island Fox funded a research study by Stacy Baker and Juliann Schamel, via a donation from Safari West, to investigate the use of cementum analysis as a method to determine island fox age at death. The results are in and the answer is, well mostly yes, but...

To conduct the analysis 31 teeth from island foxes, whose age was known when they died, were sent off for testing. Of the 31 samples, 28 were aged accurately to within 1 year of their known age, two teeth were underestimated by 3 years and one was underestimated by 4 years. This underestimation primarily occurred with older foxes.

plot of accuracy in aging island foxes using tooth cementum, S. Baker 2021

The data suggests that for younger and middle age foxes–up to approximately age 7–cementum analysis can provide an accurate assessment of age at the time of death. (A more accurate assessment than estimating age by tooth wear.) For more senior island foxes, however, the accuracy of the method drops significantly. 

What are the factors that led to a misread of the older fox teeth? 

According to Baker, the study's principal scientist: "Tooth condition may perhaps play a role, as two of those teeth out of four were determined to be of lower quality for aging according to the Matson's Lab. This also may be unavoidable, since broken and decayed teeth become more prevalent as individuals age." (Matson's Laboratory in Manhattan, Montana, specializes in aging mammals using teeth.) With the limited sample size from the older fox population, more analysis is warranted to tease out the factors that may play a role in the reading error. In the wild, foxes are known to live 10–12 years on some islands. (K Dearborn personal communication)

Friends of the Island Fox is committed to research that will expand understanding of island fox biology and behavior. The more we know about island foxes, the more we can protect their future. It's Science for Fox Sake! - Mike Watling, FIF President

Full Report: Using Cementum Annuli to Estimate Age in Island Foxes by S. Baker, 2021 

This research project was made possible through Friends of the Island Fox, a donation from Safari West, and in partnership with the National Park Service, Santa Barbara Museum of Natural History, and UC Davis.