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.

Friday, October 08, 2021

Can I Feed An Island Fox?

Please don't feed island foxes.

If there is one thing to remember when you visit the Channel Islands, this may be the most important. Wild animals who receive food from people frequently pay the consequences.

Emily Hamblin, Senior Wildlife Biologist on Catalina Island conveyed the news about a female fox. "We were very saddened this month to receive a call about a roadkill fox [hit by a car] on Stage Road. As soon as we heard the location, we knew which fox we were going to see."

The female Catalina Island fox was first caught as a pup in 2012. Most years she was captured and given a health check. There were physical signs that she had mothered pups. This year she received her health check and, despite being an older fox at nine years old, she was in good health.

"She was always gentle, didn't bite," Hamblin wrote, "and was easier to work with than the average fox. After we released her, she stayed nearby in the road instead of running off. From these actions, it was clear she was being fed by humans."

It was just two days after her health check that Hamblin was retrieving the female fox's body from the road. Part of the biologist's job is to investigate fox deaths. 

"It is hard for me not to feel a bit of hopelessness as I respond to these calls over and over again...When people feed foxes on the road, they are essentially conditioned to think that dinner is in the middle of the highway. Far too often, this behavior results in foxes being unintentionally lured to their death."

This island fox's death was preventable. 

We can warn drivers about foxes near roads. We can provide Fox-Safe bins to keep island foxes out of trash and lockers for campers, but only people can make the choice to protect island foxes. 

When you feed an island fox, you threaten its life. Island foxes that seek food from people end up entrapped, entangled, and in danger.

Save an Island Fox - Don't Feed It.

Read Emily Hamblin's full story in the Catalina Islander

Friday, September 24, 2021

Help Protect The Biodiversity of The Channel Islands

Friends of the Island Fox joins with Channel Islands National Park, The Nature Conservancy, Catalina Island Conservancy, and other conservation partners to encourage mindful visiting to California's Channel Islands.

Our Channel Islands are home to many unique species, like the island fox, which are found nowhere else in the world.

Channel Islands National Park says: "Preventing the re-introduction and establishment of nonnative species is vitally important to preserving the nearly 150 endemic plant and animal species of the islands. As a visitor, you play a valuable role in helping to protect that biodiversity."

The Nature Conservancy reminds everyone that many island plants and animals have been negatively impacted "by the introduction of harmful nonnative species, such as rats, Argentine ants, and weeds. This video provides simple steps that visitors can follow before they depart the mainland to protect the vulnerable island species."
Share this video with those you know who intend to visit the Channel Islands. Simple steps can save island foxes and other island species.

What is it like to visit:

Santa Cruz Island  

Santa Rosa Island

San Miguel Island

Santa Catalina Island

San Nicolas Island

Friday, September 17, 2021

Fox Foto Friday - Radio Collars For National Fox Day

photo courtesy of NPS

Happy National Fox Day!

Meet F269, she's a young island fox on Santa Rosa Island and she's been fitted with a radio collar funded by YOU!

 Not every radio collar is funded by a single large donation. Seven of the new radio collars currently being fitted on island foxes across the northern islands were paid for by multiple small donations. 

$20 here and $50 there quickly adds up to $220 to refurbish a radio collar or $350 to purchase a new radio collar.

Bringing small donations together Friends of the Island Fox has provided 263 radio collars for island foxes over the past 16 years.

Make a Difference for Island Foxes!

19 radio collars are being refurbished RIGHT NOW. 

FIF still needs to raise funds to pay for 11 of those radio collars. 

Every little bit will help reach that $2,420 goal for island foxes.

Why are radio collars important?

See an island fox released wearing its radio collar. 

Help Island Foxes this Fox Day!

DONATE through the secure link DONATE button on the upper right of the screen.

Friday, August 27, 2021

Radio Collars Going On Island Foxes!

photo courtesy of S. Baker, NPS

Meet M181! This young male island fox on Santa Rosa Island was fitted with a radio collar funded by YOU.

Channel Island National Park biologists have been fitting radio collars on individual foxes, conducting health checks, and counting island foxes throughout August.

These new and refurbished radio collars will provide information on island fox location and survival for the next 2–3 years.

Each radio collar has a signal at a specific individual frequency that is picked up by a radio receiver. The fox does not hear the collar's signal. 

Biologists can only hear the signal if they have a receiver tuned to the correct frequency and are within a specific proximity to the fox.

Radio collars are small and light weight so they do not bother the island fox. Each radio collar is fitted with a "two-finger fit" so that it is not too tight, yet not so loose that it might get caught on something.

Watch and Listen to the video below

WATCH as M181 is released back into the wild after his check-up and radio collar fitting.

LISTEN for the beeps from the receiver as the biologist checks the functioning of the radio collar.


Island Foxes on San Miguel Island will be getting their radio collars next.

Catalina Island foxes will be getting their radio collars and vaccinations soon. 

You can still help fund a refurbished radio collar $220 

for Catalina Island. 

Donate Today 

Friday, August 13, 2021

Island Foxes and Island Spotted Skunks Sharing Space On Santa Cruz Island

 (Thank you to our guest blogger Calypso N. Gagorik, MS in Biology, Northern Arizona University)

On the California Channel Islands, the island fox (Urocyon littoralis) has been hypothesized to compete with the smaller-bodied island spotted skunk (Spilogale gracilis amphiala). Recent declines in spotted skunk captures have led to concerns on population viability and what role the foxes may have played in the decline.

(Calypso worked in the field on Santa Cruz Island with fellow researcher Victor Zhang.

From 2018–2019, we GPS and VHF collared foxes and spotted skunks living on Santa Cruz Island to assess space use and deployed remote cameras to examine interactions between the two species at spotted skunk den sites. We also explored monitoring tools for spotted skunk detection with emphasis on remote camera placement and use of scent stations.

We found fox and spotted skunk seasonal home ranges were much larger than previously reported on Santa Cruz Island and spotted skunks moved around the landscape differently compared to foxes.  

Spotted skunks showed restricted movement, using less than 50% of their home range over shorter time periods such as a week or month. Foxed moved widely through the landscape covering more than 50% of their home range over the course of a week. During this time, we collected the first photo evidence that foxes may be disturbing resting sites of spotted skunks during the day. We also found that remote cameras placed on drainage bottoms may be more effective in detecting skunks. We discourage the use of scents at camera stations as foxes appear to be monopolizing the stations by repeated marking.

Our knowledge and understanding of spotted skunk ecology are still limited due to the many challenges of studying a cryptic species. We encourage further studies be conducted on spotted skunks, particularly focusing on interactions of foxes and spotted skunks at den sites.

Calypso Gagorik, MS Biology

Read the full thesis: Spacial Use Patterns And Management Recommendations For Two Endemic California Channel Island Mesocarnivores, The Island Spotted Skunk (Spilogale gracilis amphiala) and the Island Spotted Skunk (Urocyon littoralis)

Friends of the Island Fox provided financial assistance to this research project. 

The deadline for the FIF 2021 Research Grant is August 31, 2021 

More Island Fox Research