Friends of the Island Fox

Friends of the Island Fox is currently taking applications 

through June 30 for the 

FIF 2024 Research Grant

Download Application

From the complex relationship between island foxes and island spotted skunks, to diet, microbiome impacts on health, and changing territory sizes, research projects are revealing the complexities of the Channel Island ecosystem and the role of island foxes in island ecology.

In 2024, Friends of the Island Fox is offering up to $7,000 in support to research projects benefiting greater understanding of the island fox and the Channel Island ecosystem.

 

Last year's grant recipients are using wildlife cameras to quantify island spotted skunk populations and investigating the impact of individual island fox behavior on the island ecosystem.

It's Science, for Fox Sake! And we encourage all applicants to apply.

 

2023 grant recipient, D. Thomaier

Past Research Grant Recipients and Projects

Grant Recipients are asked to provide public updates on their work - "Date with a Fox" programs, hear from the researchers

Published science on island foxes and island spotted skunks

  Your Donations Help Fund this Important Science!

Juliann Schamel has been researching island fox diet using stable isotopes in whisker samples since 2018. Friends of the Island Fox has supported the processing of whisker samples through several Research Grants. In November of 2023, Schamel presented the following poster of her latest work at the California Islands Symposium.

Using Stable Isotopes to Assess a Decade of Dietary Resource Use in Two Sympatric Island Endemics: The Island Fox and the Island Spotted Skunk (link to complete poster)

Island foxes and island spotted skunks live together on two islands, Santa Rosa and Santa Cruz. When island fox numbers crashed due to predation by golden eagles, island spotted skunk numbers appeared to increase dramatically. In 2011, on Santa Rosa Island, there were still fewer than 90 island foxes in the wild. During annual health checks, whisker samples were collected from both island foxes and island spotted skunks in a northern area of the island and stored for later analysis of what food resources each species was using.

In 2011, island spotted skunks out numbered island foxes in the wild. Stable isotope analysis shows that the skunks and foxes were using different resources. 

J. Schamel, 2023 poster 

Carbon and nitrogen isotopes travel up the food chain leaving a specific isotope signature for plant and animal resources. Literally, you are what you eat and isotopes from a mammal's diet are laid down chronologically in hair or fur. A single island fox whisker can provide 5–6 months of weekly diet data. On the graph above, native terrestrial plant foods, like manzanita berries, are high in Carbon and low in Nitrogen. A deer mouse is the accumulation of its own, mostly plant diet; it has a mid-range Carbon and Nitrogen signature. In the graph above, the blue data points represent island fox diet and the orange data points represent island spotted skunk diet. 

In 2011, when island fox numbers in the wild were low, their diet tended

to be higher on the food chain or trophic level: deer mice, birds and

reptiles. The data suggested separate diet niches for island foxes and island

spotted skunks. The skunks were eating primarily, lower level prey, like insects, and some plant foods.

J. Schamel, 2023 poster

In 2014, continuing drought influenced wildlife survival; island fox and island spotted skunks were nearly even in number on Santa Rosa Island. Island foxes expanded their diet, including marine resources, and island spotted skunks preyed more on deer mice and higher level prey. The two predators began competing for resources.

J. Schamel, 2023 poster

By 2018, the island fox population had recovered, but island spotted skunks appeared to decline in number. (Counting island spotted skunks) As island fox density increased across the island, they dramatically broadened their diet–from native fruit through a range of prey species. The spotted skunks maintained a more narrow diet, but they were now in constant competition with island foxes. What will this mean for the two species?

Schamel's work also revealed that individual island foxes are becoming specialized in their diet.

J. Schamel, 2023 poster
 

In the graphic above, each circle of data points represents an individual island fox and its diet. Some individuals appear to be specializing in fruit and insects, while others are eating predominately terrestrial prey. How is island fox diet continuing to change?

Save the date of April 30th at 6:30 pm PT 

Juliann Schamel will talk about her work on 

FIF's "Date with a Fox" webinar

sign-up for FIF's e-newsletter to receive an invitation

Measuring out a whisker sample

Whisker samples continue to be collected for both species. 

designed by island biologist, Stacy Baker

When you purchase an island spotted skunk pin, 

you send a sample of island spotted skunk whisker 

to the mass spectrometer to reveal stable isotopes.

 

Are island spotted skunks genetically different enough from mainland spotted skunks to warrant species status? FIF 2022 Research Grant recipient Julia Owen is probing the island spotted skunk genome.

 

Are island foxes crossing into the territory of other island foxes to access beach foods on Santa Rosa Island? FIF 2021 Research Grant recipient Katie Elder and recipient Juliann Schamel continue to investigate island fox territory size and diet. 

Are you investigating island foxes, prey species,

Channel Island ecosystem dynamics, public education and attitudes toward

island fox conservation, or any topic relating to island fox survival and a healthy island ecosystem?

Apply for FIF's 2023 Island Fox Research Grant

Download Application

Grants will be considered for up to $7,000

Application Deadline August 28 

Friends of the Island is taking applications through August for the FIF 2023 Research GrantDownload APPLICATION From dietary investigation linked with territory use to microbes affecting island fox health, new science is revealing the complex world of island foxes and the Channel Island ecosystem. This year FIF will be offering up to $7,000 in support toward research projects benefiting greater understanding of island foxes and the Channel Islands. Last year's grant project is working to reveal the Spotted Skunk Genome and how the island spotted skunk is related to mainland populations. Island spotted skunk origins may help support evolving information on how island foxes initially arrived on the Channel Islands. More on current and past FIF Funded Research FIF grant winners are asked to provide public updates on their work.  See presentations by Fox Researchers for "Date with a Fox" programs Recently published island fox science Important island fox research is funded by DONORS LIKE YOU. It's Science for Fox Sake!   

island fox pup, courtesy of I. Rose Across the Channel Islands, island fox parents are finding hidden-away spots for a den where females can give birth to pups. Most island fox pups are born in April. How big are island fox pups at birth? Small - about the size and weight of two AA batteries. What do you call baby island foxes? Pups or kits. At birth their natal fur is a cocoa brown and their ears appear small and rounded. The pup pictured was born at a zoo in 2006–at that time there was a small breeding population in a few zoos. Island fox dens are not disturbed in the wild. When do pups emerge from the den? Typically in June. When pups come out into the world they have replaced their baby fur with a coat that looks like their parents. Island fox fur How many pups are in a litter? Typically, 2–3 pups are born in a litter. Play between siblings is an important part of learning to hunt and interact socially. If food resources are abundant, an island fox pair can have up to 5 pups. In years of drought, few pups are born. Drought year, 2021 What sounds do pups make? LISTEN to the sounds of a young island fox pup. What do they eat? Like all mammals, island fox pups initially nurse milk from their mother. Gradually, they eat prey brought to them by both of their parents. The parent above is bringing 3 island deer mice back to the den. Both parents teach the pups to hunt and find plant foods. Island fox diet Are island foxes born knowing how to hunt and find food? No. All of the island foxes currently in captivity were pups that were separated from their parents and did not learn how to provide for themselves in the wild. Island fox pups need their parents to teach them how to hunt and find food. Video - Island fox pup reunited with mother  

  Small pieces of island fox whisker can reveal big data on island fox diet and behavior.  Analyzing stable isotopes in slivers of island fox whisker, Juliann Schamel (Research grant recipient 2018 and 2019) has been uncovering the range of diet eaten by island foxes, drought impacts on their diet, and a new understanding of how some island foxes use marine resources. Your scientific research could also benefit island fox survival and the management of rare and endangered species. Friends of the Island Fox is accepting applications for the 2022 Island Fox Research Grant through August 29, 2022. Application More about current island fox research and recent grant recipients. Your donations help support vital island fox research. 

This is a GPS radio collar being prepped to be worn by an island fox this summer. Katie Elder was FIF's 2021 Research Grant recipient and she will be investigating territory size on Santa Rosa Island. More on her work Friends of the Island Fox is taking applications for our 2022 FIF Research Grant now through August 29, 2022. Application What will you uncover about island foxes? Research in island fox ecology is an investment in the future and island fox survival. Not only is this work important for island foxes and the Channel Islands, but also for other endangered species with small population sizes in confined geographic habitats. An island doesn't have to be surrounded by water, it can be a confined habitat surrounded by desert, a city, or some other physical barrier. Population viability calculations used for island foxes have been applied to the Sierra Nevada red fox. See more on Current FIF Funded Research Projects Recently published island fox discovery  Discussion on island foxes and island spotted skunks Update on island fox microbiome research

In 2018 Juliann Schamel was the recipient of Friends of the Island Fox's first Research Grant. Her investigation of island fox diet through stable isotopes in whiskers has evolved and deepened to look for connections between diet and surviving drought conditions.  In 2019 FIF continued to fund Schamel's research as she followed the foxes and the potential of "beach foods" in their diet. It is no coincidence that the island fox above is in a beach area.  If you look closely at the pile of kelp washed up on the beach, or "beach wrack," you'll see island fox foot prints all around it. photo courtesy of Nick Schooler, UCSB Combining her stable isotope research with collaborators at the University of California, Santa Barbara, Schamel has revealed that some island foxes are making use of food resources connected to sandy beaches. Tiny arthropods called "beach hoppers" live in the sand and emerge to eat the kelp that washes up on the beach. Look closely and you will see a group of them feeding on the edge of the kelp blade pictured.  Some island foxes are eating these tiny, quick moving creatures. If you've turned over a clump of beach wrack and seen little hopping critters, commonly referred to as sand fleas, you've seen beach hoppers. They are not fleas at all; they are more closely related to shrimp. Juliann Schamel recently presented a poster at the 2022 Wildlife Society Conference. POSTER And her paper Diet of a threatened endemic fox reveals variation in sandy beach resource use on California Channel Islands with Henry M. Page, Marine Science Institute, UCSB, et. al. was published in PLOS ONE. Read the Paper Your support for FIF helped fund this important research. The island fox and the beach hopper demonstrate an intertwining of terrestrial and marine ecosystems on the Channel Islands.

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.

 (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