The Legacy of Island Fox M152

Island fox M152 became known to all of us in 2018.

We watched this male fox on Santa Rosa Island get a radio collar. His health check was profiled and compared to his health history. Over the summer he avoided capture for 2019 health checks, but through September his radio collar tracked his normal activity.

Recently we received notification from the National Park biologists: "We are sad to report that M152's mortality was confirmed...on October 12."

M152 appeared to have died right after the biologists left Santa Rosa to do health checks on San Miguel in late September/early October. Though he appeared to have died from natural causes, his body had gone undetected too long in the warm weather for a necropsy to determine exact cause of death.

But because M152's radio collar signaled his death, and biologists were able to find his body. That means his story continues:

M152 was found quite a way from the location where he had been captured in 2014 and 2018. It may be that the reason he was not consistently captured was because his territory only tickled the area where foxes are counted.

Despite his death, a whisker sample was taken from M152. This will add to the cumulative story of his diet through the stable isotope study (supported by FIF). Researchers will be able to chronicle his diet through the drought and back into a rainy 2019. His whisker will also provide information on what he was eating or how his diet changed as he neared the end of his life.

Biologist Juliann Schamel says, "M152 was one of the few collared foxes on Rosa whose exact age-in-years we don't know..." When he was first captured in 2014, it was estimated that he was 1–2 years old, by looking at the wear on his teeth. 

His canine teeth have been preserved. A FIF funded research project in progress is evaluating if structures in the canine tooth can be used to verify island fox age at death. If this research is fruitful, we may be able to determine M152's age when he died. Was he the 6–7 years old that was estimated or was he older?

M152's radio collar still had two years of battery life, so it was cleaned up, disinfected and deployed on a male fox born in 2019. Male pup M164 was collared in November in the Cherry Canyon area. Cherry Canyon is frequently visited by day hikers on Santa Rosa. Because young males under a year old tend to disperse to find their own territory, M164 may take this story into a completely different part of the island.

M152 was the fox face that encouraged donations in 2019 and helped fund a record 40 radio collars for island foxes across the Channel Islands. We are sad to say "farewell" to him, but his legacy lives on.

Fox Foto Friday - Happy Foxgiving

Across the Channel Islands, island foxes thank you.

These rare creatures live only on six islands and no where else in the world. (About Island Foxes) Your concern and donations have helped bring them back from the edge of extinction and are vital to protecting their future.

What Can We Learn From An Island Fox Tooth?

How do we estimate the age of island foxes? In the past, age has been estimated by visible wear on the first upper molars. This method is imprecise because island foxes have varying diets and sand may be consumed while island foxes are foraging. Sand can add excessive wear to teeth. A two-year old fox living along a shoreline or in a dune area, may have more wear to its teeth than a five-year old fox living in an island's interior.

male canine tooth from Santa Rosa Island

Friends of the Island Fox is excited to fund research into a scientific technique, which may determine the age of a fox after it has died. A donation from Safari West has enabled FIF to fund a second research project this year with investigators: Stacy Baker and Juliann Schamel.

What Is the Research?

Most wild mammal teeth annually add a layer of a hardened substance called cementum along a tooth's root. When the tooth is divided horizontally, rings of the layers become visible. Counting these rings can provide the animal's age at the time of death. Baker and Schamel will work with the Santa Barbara Museum of Natural History and the University of CA, Davis, to analyze canine teeth from deceased island foxes. Analyzing tooth samples from island foxes with known ages at the time of death will help verify the methodology.

Why Is It Important?

An island fox that dies when it is 9 or 10 years old is a mature adult. It probably has had an opportunity to reproduce and pass on its genetic diversity. An island fox that dies when it is 2 or 3 years old is still a young adult. It may not have had the opportunity to successfully reproduce. To make the best long-term conservation decisions, it is important to understand the age of island foxes at their death. 

If this technique works for island foxes, it will provide valuable data to inform a variety of questions:

• How does tooth wear vary from island to island?
• Which age group of island foxes are most likely to be hit by cars on populated islands?
• Is there a difference in lifespan between males and females?
• Is lifespan different from island to island?
• Can this method identify when the lifespan of a specific island fox population is changing?

This last question is very important. If young foxes become the largest group suffering moralities or if the lifespan on a specific island begins declining, investigation and conservation efforts are needed immediately.

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.

This research is entirely funded by donations. 

Your donations make a difference.

More Island Fox Research:
FIF Research Grant - Whisker Isotopes 2019
FIF Research Grant - Whisker Isotopes 2018

Other Island Fox Research Papers

Health Checks for Catalina Island Foxes

biologist checks island fox's teeth

Across Catalina Island biologists are counting island foxes and giving them health checks. Foxes are caught in safe capture cages.

Catalina's population has recovered from the 1998 crisis caused by the introduction of the disease canine distemper. It is natural for populations of wild animals to adjust from year to year. We now know there is a direct connection between rainfall levels and successful island fox reproduction.

The return of drought conditions in 2018 caused an estimated 20% decline in island fox numbers on both Catalina Island and Santa Cruz Island. The Good News is everyone expects 2019's return of normal rainfall levels and a cool spring will bolster plant and animal resources and restrengthen island fox numbers.

We'll be waiting to hear what the biologists find in the field.

island fox receives a distemper vaccination

Lara Brenner, Wildlife Biologist for the Catalina Island Conservancy (CIC), reminds everyone that "Disease is the number one threat to Catalina Island Fox populations." During health checks, biologists monitor fox weight, body condition, and look for "new and emerging health issues."

Catalina is the most visited Channel Island. "Visitors can help protect the Catalina Island fox from disease," Brenner says, "by keeping their pets on a leash when not indoors and by staying up-to-date on your pet's vaccinations." No one wants their pet to pass-on or receive an illness while on vacation.

Wild raccoons are still a possible way for disease to be introduced to any of the islands. Brenner reiterates "Boaters should check their craft for stowaway, non-native animals (like raccoons) that could transmit a fatal disease." 

These simple actions are big steps toward protecting island foxes.

 

Fox Foto Friday - Where's M152?

Remember this face from last year? M152 is a male fox on the eastern side of Santa Rosa Island. 

This year he was not counted during the annual count and health checks in his area. But don't fear... M152 is doing well. We know he is still in his territory and going about his daily life because he is wearing a radio-tracking collar.

This demonstrates the importance of having two ways to monitor island foxes. 

Annual counts and health checks allow biologists to check the health and well-being of individual animals while they have them in-hand. This provides a snapshot of the population's health as a group at a specific time.

Radio-tracking collars enable the monitoring of individual foxes throughout the year. Their movements in an area can be tracked and if something happens to them, their radio collar reports to  biologists.

M152 did not come into a capture cage this year. Perhaps he was finding plenty of food because of the normal rainfall this spring and saw no reason to enter a capture cage. Perhaps when he came across a capture cage, another fox was already in it.

M152 is a pretty wily fox. We think he is approximately 5–6 years old. In that time he's only been captured twice: in 2014 and last year in 2018. ID micro-chips make is possible for each island fox to be tracked as an individual.

We're sorry that the biologists didn't have a chance to weigh him, check his health, and take a whisker sample this summer. It would have been great to compare to his last health check.

But other foxes did get examined and their stories are important too.

Fox Foto Friday - Time for Health Checks!

Across the Channel Islands, island foxes are being counted and given health checks. This island fox on Santa Cruz Island also received a refurbished radio-tracking collar funded by Friends of the Island Fox. See her as she is released.

For the next three years this radio collar will tell biologists that this island fox is up and moving around in its environment. It will also give off a mortality signal to alert biologists if something should happen to this individual island fox. Rapid response to mortalities enables a quick response to disease or threats to other island foxes. 

What are the current threats to island foxes in 2019?

FIF Research Grant to Investigate Further Into Island Fox Diet

Friends of the Island Fox is happy to announce that Juliann Schamel's research investigating island fox diet through stable isotopes in whisker samples has been chosen to receive the FIF Research Grant for 2019. 

an island fox stash of deer mice

This second year of support will enable analysis of additional data sets to identify seasonal dietary items during drought and important to successful reproduction. It has long been believed that deer mice are a vital food item during breeding and pupping season. Is it true? Does availability to a specific food source influence successful reproduction? If island foxes do not have accesses to abundant deer mice are they less successful as parents?

The grant will also expand the study to look at island fox use of marine resources. Do island foxes use marine foods during drought? If so, which island foxes are able to make use of marine resources?

Island fox whiskers provide an amazing record of what an individual island fox has been eating over 5–6 months. All food items are made up of carbon and nitrogen, but each kind of food has a different balance of elements and therefore a different signature. These individual isotope signatures are recorded in the fox's whisker. More on Schamel's initial research.

Schamel's initial whisker data set went to the lab this spring. At the Center for Stable Isotopes at the University of New Mexico, each individual whisker is divided into tiny sections and processed in a mass spectrometer.

An island fox that eats the same kind of food (all deer mice or all plant fruit) for a period of time will show an isotope graph that is fairly flat. The mixture of carbon to nitrogen will remain the same. But if an island fox changes up its diet dramatically, a spike will appear in the graph showing a change in the isotopes laid down in the whisker.

Comparing these results for known individual island foxes, living in known habitats, will provide valuable data on how sustained drought impacts island fox diet and how diet impacts their ability to survive and thrive.

The FIF Research Grant is completely funded by YOU. Without your donations to FIF this research would still be a dream. 

Donate today to support island fox conservation research.

Thank you to all of the 2019 grant applicants for sharing your research goals with FIF. There is so much more to learn about island fox health, behavior, and interactions with other species.

Applications for the 2020 Research Grant
will be available April 15, 2020

  

Fox Foto Friday - The Endangered Species Act Saved This Fox

 Just over two years ago, the Channel Island fox was removed from the Endangered Species List.

The Endangered Species Act saved this fox!

 Survival shouldn't be political.

 

Saving a species is a very complicated task, and it requires a coalition of people all working together to make it happen. 

We shouldn't abandon the Endangered Species Act.
We should embolden it, embrace it, and help the world become a better place. 

The Endangered Species Act (ESA) has provided the necessary protection and attention to help save four subspecies of Channel Island foxes from extinction.

Downloadable island-by-island report Island Fox Update 2018. 

Working Together To Save The Channel Island Fox 

2019 Island Fox Status Update

In 2018 most island fox populations were stable, but not without risk factors. 

As expected, high temperatures and below average rainfall in 2018 contributed to lower pup numbers and reduced adult survivorship across all islands. As first documented on Catalina Island, island fox reproduction is linked to annual rainfall. Fortunately, normal rainfall levels in 2019 should benefit all island fox populations.

In 2019 Channel Island foxes face four major threats:

• climate change: increasing regional temperatures and decreasing annual rainfall, which reduce food resources, increase wildfire threat, and promote parasite numbers
• biosecurity: the introduction of non-native plants, animals, and diseases
• parasites: rising tick numbers and tick-borne diseases; increased intestinal parasites on some islands
• reduction of management funding

The following update is drawn from FIF notes taken at the 2019 Island Fox Conservation Working Group meeting. Population numbers reported here are the official estimates from each island manager, as calculated from the fall 2018 count and reported May 21, 2019. Download the detailed 2019 Island Fox Status Update

Greatest Concern 
San Miguel Island foxes robustly recovered from 15 individuals in 2000 to over 500 by 2010 (lime-green line on graph below). As a smaller island, it will always have a smaller fox population. In 2015, however, following several years of drought, the population began declining. As of fall 2018, the population has dropped to an estimated 171 individuals (a decline of over 70%). This decline may involve several interconnected threats: climate change, biosecurity and parasites. Details regarding San Miguel will be posted in coming days.

Improved
San Nicolas Island foxes declined by 59% to 260 individuals during consecutive years of drought from 2012–2015 (pink line on graph above). The US Navy initiated native plant restoration projects in conjunction with Channel Islands Restoration. As these plants, like prickly pear cactus, mature they are providing food and habitat for island foxes and prey species. The fox population has increased to a more stable number–estimated 400 individuals. 

Stable
Santa Rosa Island foxes may have reached capacity for the island (pink line on "larger islands" graph above). Native vegetation is recovering and increasing resource options for foxes during periods of drought. No island foxes have been lost to golden eagles on this island or San Miguel since 2010. Parasites, including tick-borne disease, are a growing concern on Santa Rosa. FIF has refurbished 7 radio collars, and funded dietary research and health testing measures in 2019.

Santa Cruz Island foxes have reached capacity for their habitat. As a result the population decreased naturally during 2018 (green line on "larger islands" graph above). Parasites, especially tick-borne Lyme disease, are an increasing concern. Because the Cruz population has been stable since 2014, there is pressure to reduce funds for monitoring. This poses a potential threat because this population receives elevated contact from the outside world via island visitors. FIF has refurbished 20 radio collars for monitoring in 2019.

Santa Catalina Island foxes have also reached capacity for their habitat. In reaction to decreased rainfall, this population also declined naturally in 2018 (red line on "larger islands" graph above). Parasites, especially tick-borne Lyme disease, and biosecurity are an increasing concern for this population. Lyme disease and canine herpes virus were both introduced via human visitors and their pets. Monitoring of disease exposure is vital to this populations continued health. FIF has funded 5 new radio collars and health testing measures in 2019.

San Clemente Island foxes live on the most southern Channel Island (blue line on "smaller islands" graph above). In 2018, they were the first population to see deaths directly attributed to high temperatures. Reduced rainfall stressed the population and eight individual island foxes are known to have perished in the heatwave between June and July of 2018. Climate change is impacting this island fox most directly. 

Download the detailed 2019 Island Fox Status Update

Fox Foto Friday - What's That Island Fox Wearing

Yes, it is a new radio-tracking collar! 

Through your generous donations, FIF was able to fund 5 new radio-tracking collars for island foxes on Catalina Island. 

Catalina Island fox receives vaccination during health check

These new collars will be placed on island foxes during this summer/fall annual counting and health checks.

Are you keeping count? We are:

• 7 refurbished collars for Santa Rosa/San Miguel
• 20 refurbished collars for Santa Cruz
• 5 new collars for Catalina

Our goal is to fund 8 more $220 refurbished collars for Santa Rosa/ San Miguel in 2019. 

With your help we can meet this important need.  

Please donate today

Bald Eagles Thriving and Maintaining Island Balance for Island Foxes

Across the Channel Islands, 2019 has been the best year for bald eagle reproduction since recovery efforts began 35 years ago. This spring 24 bald eagle chicks successfully fledged from nests. (That means they survived to fly.)

According to a press release from Channel Islands National Park: "This year there were 19 breeding bald eagle pairs on the Channel Islands producing 24 chicks, including 10 on Santa Cruz Island, 9 on Santa Catalina Island, two each on Anacapa and San Clemente Islands, and one on Santa Rosa Island."

Orange wing-tags mark Catalina-hatched bald eagles

Bald eagles are a vital part of the Channel Island ecosystem. As fishing eagles, they prey primarily on fish and other birds, as well as consuming carrion. Bald eagles do not typically eat mammal prey and therefore are not usually a threat to island foxes.

On occasion island foxes climb up into bald eagle nests. For the most part the foxes act as a clean-up crew picking up tidbits of food left behind by eagle chicks. Eaglets are typically either protected by a parent when very young or too large for island foxes to prey upon.

blue wing-tags mark no. island eagles

Bald eagles therefore help transfer vital nutrients from the marine environment up onto the island. They help provide marine resources to island foxes, deer mice, and the island ecosystem. Nitrogen and calcium from fish are dropped on the land or eaten and deposited via scat. Marine resources can then help to fertilize island plants.  

Island foxes and bald eagles lived in balance on the Channel Islands for thousands of years. The oldest bald eagle fossils found in Southern California are 35,000 yrs old and from the La Brea Tar Pits. Bald eagles declined between 1945 and 1960 because of the insecticide DDT which had been introduced by people into the surrounding marine environment. DDT and bald eagle.

Bald eagles historically kept golden eagles from colonizing the Channel Islands and, in doing so, protected the island fox. Though they are both called "eagles," bald eagles (Haliaeetus leucocephalus) and golden eagles (Aquila chrysaetos) are not closely related. They come from two distinct evolutionary branches of predatory birds that separated and became competitors more than 12 million years ago. (By comparison, humans and chimpanzees diverged from a common ancestor just 7 million years ago.)

Golden eagles are mammal predators; they specialize in hunting small mammals about the size of a football (rabbits, ground squirrels, deer fawns, marmot, etc.) . Golden eagles hunt island foxes. They also eat carrion. Because both species will eat something that is already dead, they are known to take food from each other. There have been accounts of a bald eagle taking a dead island fox body from a golden eagle.


These two large birds have evolved to specialize in different food, but they compete for territory and nesting sites. Around the world fishing eagles and mammal-eating eagles are in competition with each other. You might think of them like dogs and cats–they share an ancestor, both are predators, but they have different specializations. They put up with each other at times, they will steal food from each, and in a confined space, like the islands, they just don't get along.

Though both bald and golden eagles are similar in size, resident bald eagles on the islands are frequently in mated pairs. Golden eagles encountering the islands are typically migrating individuals. This two-on-one situation gives bald eagles the upper hand.

When the Channel Islands' bald eagle population is thriving, there is no room for golden eagles and the habitat is safer for island foxes. Check out live bald eagle nest cams on the islands: http://www.iws.org/livecams.html

Foxes on Santa Cruz Island are Wearing FIF Collars

This island fox was captured and counted this week on Santa Cruz Island. 

She received a health check and her radio-tracking collar was replaced with a newly refurbished collar. Her old collar will come off and be eligible for refurbishing. 

Earlier this year, 20 radio collars from Santa Cruz Island were sent in for refurbishing and funded by FIF.

In just a few minutes this little fox was released back into the wild. Her refurbished radio collar has a battery that will last 2-3 years.

Her microchip enables biologists to identify her as a specific individual. If she is caught again this summer, the microchip reader will quickly identify her so that she can be released immediately without being handled.

Your donation of $220 would recycle her used radio collar to be placed on another island fox.

Research Grant Deadline - July 12, 2019

The more we know about island foxes, the better we can play a positive role in their continued survival.

Friends of the Island Fox is accepting proposals for research projects that improve our scientific understanding of island foxes. Grant funding up to $5,000 is available.

The deadline for this year's applications is July 12, 2019.

For more information and an application

Friends of the Island Fox Funded Research

Whisker Isotope Study Update - Juliann Schamel

Other Researchers:

• Nicole Adams - Island Foxes, genetic diversity and the immune system
• Courtney Hofman - DNA and the Origin of the Island Fox 

We hope you are noticing that island fox research is filled with innovative women.

For other research regarding island foxes: 

Island Fox Research

Fox Foto Friday - Radio Collars Going On Island Foxes

photo courtesy of M. Navarro, CINP

Island foxes on Santa Cruz Island are receiving health checks and being fitted with newly refurbished radio tracking collars RIGHT NOW!

You refurbished these radio collars and today they are going on island foxes.

More Radio Collars for Island Foxes !

This island fox is smiling because it is wearing a newly refurbished radio collar. More about M152

Two things happened this week:

• 7 newly refurbished radio collars arrived at Channel Islands National Park to be deployed on San Miguel and Santa Rosa Island foxes
• FIF funded our 27th radio collar this year!

Twenty refurbished radio collars went to Santa Cruz Island in May to be fitted on island foxes this summer. 

You helped fund these radio collars to monitor island fox health and welfare. 

But we aren't done yet. 

Health checks and annual counting are starting across the islands. This is when old damaged radio collars are removed and replaced with new or refurbished radio collars. 

 

FIF is hoping to fund:

• 5 more $350 new collar
• 13 more $220 refurbished collars 

We know we can do this with YOUR HELP!

The time to radio collar island foxes is right NOW! 

Please DONATE TODAY 

FIF Funds Important Health Investigations for Island Foxes

Why are these biologists smiling? Because you are helping island foxes.

Mike Watling (FIF) presents funds to Lara Brenner (CIC) and Laura Shaskey (CINP)

At the annual meeting of the Island Fox Conservation Working Group, Mike Watling, a member of the Friends of the Island Fox Advisory Committee, presented FIF donations to support important investigations into the health of island foxes.

$3,000 to the Fox Program at Catalina Island Conservancy

tick attached to fox lower eyelid

This funding will test a second year of tick samples to determine the threat to island foxes from Lyme disease introduced to several islands in 2018. More on tick-borne disease testing. 

It also represents support from a Fresno Chaffee Zoo Wildlife Conservation grant that will analyze blood samples from island foxes on Catalina for signs of introduced disease. Once again a stow-away raccoon was recently stopped before hopping from a private boat to Catalina Island. Introduction of new diseases via pets and transported wildlife continue to be a problem for all islands, but especially Catalina. In 2018, blood samples revealed for the first time that a small number of Catalina Island foxes were exposed to a form of canine herpes virus. This important testing also detected exposure to a common dog illness, Coronavirus. 30% of the tested island foxes had been exposed to Coronavirus. Fortunately, no island foxes are known to have died from this disease.

$2,000 to the Fox Program at Channel Islands National Park
Intestinal parasites are causing early deaths among island foxes on San Miguel Island. This funding is part of a multi-pronged investigation to understand why and how new parasites are plaguing foxes on this island and why well-known parasites are causing greater impacts on San Miguel Island foxes. (see other ways FIF is helping this investigation)  

When you donate to FIF 

your donations go right to work helping island foxes.