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 If the data on territory size is outdated, population estimates could be over- or understated.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.

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References:

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.

Fox Foto Friday - FIF Research Grant Deadline Approaching

 

$5000 in research grant funding is nothing to stick your tongue out at.

The deadline for Friends of the Island Fox's 2021 Research Grant is fast approaching.

Download FIF 2021 Research Grant Application

Applications will be accepted through August 31.

 

Join the innovative researchers discovering new information about island foxes and the Channel Islands.

Fox Foto Friday - Island Fox Science in Progress

What are these? Look closely. These are swabs from island fox ears and backsides being processed in the lab at the Smithsonian Conservation Biology Institute in Washington D.C.

This is island fox science in progress! FIF 2020 Research Grant recipient Dr. Allie DeCandia updated us on her work investigating the microbiome of island foxes.

"Between July and December 2020, collaborators across all six Channel Islands collected ear canal swabs, anal swabs, and blood samples from 50–60 foxes per subspecies. After collection in the field, these samples were shipped to Princeton University for temporary storage until all samples arrived on the east coast." In March, DeCandia moved the samples to her lab at the Smithsonian. She spent April and May inventorying samples.

"My collaborators did a fantastic job sampling foxes!" DeCandia says. "In total, I inventoried 851 swabs over the course of 23 hyper-focused laboratory hours (which were thankfully not consecutive)."

Processing the samples must be meticulous because she is investigating DNA.

"I sterilized scissors (bleach dunk / water dunk / superheat in a Bacinerator), snipped off the swab tip, placed the swab tip in a sterile microcentrifuge tube, recorded metadata written on the original swab container, and repeated the process for each swab collected."

The coordinating 300+ blood samples are now being inventoried and the individual island fox DNA extracted. DeCandia will spend the summer extracting microbial DNA from the swabs and preparing samples for "microbiome sequencing." Over the fall/winter, she'll be deep in analyzing the data.

"I am ecstatic to be working with so many amazing researchers in the field and in the lab," DeCandia says, "and can't wait to analyze this impressive dataset in the months ahead!"

FIF grant funds are processing the DNA extraction. 

Your donations support this cutting edge research.

If an island fox is an environment for microbes, what was lost when island fox populations declined to just a few individuals? How is an entire species' health impacted if they recover from near extinction, but have lost some of the microbial biodiversity that protected them from bacteria infection or supported healthy digestion? 

Island fox microbiome investigation will help us understand island fox health and may have implications for other endangered species.

Your donations supporting research are an investment in the island fox's long-term survival.

Friends of the Island Fox is taking applications

through August 31 for our 

2021 Research Grant  (see application)

Investigating the Relationship Between Island Foxes and Island Spotted Skunks

Islands typically support few terrestrial, or ground-living, carnivores due to the challenges of traveling over water to arrive on islands. On Santa Cruz and Santa Rosa Islands we have the rare occurrence of  two insular carnivores: the island fox and the island spotted skunk (Spilogale gracilis amphialus).

How the skunk got to the islands remains unclear, yet evidence has shown they have existed with the foxes for at least 7,000 years. (Fox arrival on the islands)

The spotted skunk and island fox are rivals, competing for the same resources in the form of aggression and predation. Averaging 3–4 lbs on the northern islands, the island fox is the larger and more dominate species. Island spotted skunks are about half the size. However, there is little understanding of when and where these two species interact.

In 2020, Friends of the Island Fox provided some funding to aid in a better understanding of the activity pattern of skunks and foxes on Santa Cruz Island. (More on FIF Research Grants)

Modern Global Positioning Satellite (GPS) collar technology can now capture additional information from wildlife that was not previously accessible–including accelerometers, which measure the forces of active movement. In this study, several foxes and skunks were fitted with GPS and accelerometer enabled collars to map the movement of each species with the aim of revealing the environmental factors that are most important in driving the fox's activity, such as changes in temperature, reproduction, and/or competition.

Researcher Calypso Gagorik with island spotted skunk

Calypso Gagorik, the project's principle investigator, says: "Given that the spotted skunks are strictly nocturnal, the chance of fox-skunk encounters may be entirely driven by changes in daily fox activity patterns."

skunk radio collar

The map below shows the GPS data points of one spotted skunk and one island fox that have overlapping home ranges. (Red dots represent island fox locations and Blue indicators are island spotted skunk locations. Skunk locations are taken less frequently because the batteries on their collars are considerably smaller. Each GPS location mark requires battery use.) What still needs to be analyzed is whether the fox and skunk were active at the same time of the day.

 

The importance of this research according to Gagorik, is "if foxes and skunks utilize similar area, but are active at totally different times, then the chance of interspecific interactions may actually be quite low." In other words, an island fox might visit a water source during the day, while the island spotted skunk might drink from the same location at night.

Researcher Victor Zhang with spotted skunk

Previous accelerometer data that was collected in 2019 have informed Gagorik and, fellow researcher, Victor Zhang "that the timing of daily fox activity varies greatly across the year, and the current analyses (completion summer 2021) will aim to reveal the environmental factors that are most important in driving changes in fox activity timing." Island foxes may be hunting prey at night during the winter and feeding on fruit during the day in summer. Gagorik adds, "Knowledge of these relationships will allow us to better predict the behavioral responses of both species to environmental change, as well as generate new knowledge on fox and skunk ecology." (Calypso Gagorik, email communication).

Previous data has shown that foxes occupy a flexible niche within the island community. They possess the ability to take advantage of the various habitat types, which make up the Channel Islands. On the other hand, the island spotted skunk may have a more specialized niche driven by fox activity.

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 better we will ensure a future for both species.

 

"Examining temporal niche and movement patterns of the island fox (Urocyon littoralis) and the island spotted skunk (Spilogale gracilis amphiala) on Santa Cruz Island, CA" was investigated by Calypso Gagorik and Victor Zhang in conjunction with Northern Arizona University and under the supervision of The Nature Conservancy.

FIF is accepting applications for our 2021 Research Grant thru August 31, 2021

Friends of the Island Fox 2021 Research Grant

Applications for Friends of the Island Fox's 2021 Research Grant are now available.

Slide of tooth sample from deceased island fox

Structures in island fox teeth may help clarify island fox lifespan.

Whisker samples can provide data on island fox diet.

Part of FIF's mission is to support research that will help build scientific understanding of island fox biology, health, behavior, ecology, and any aspect that influences the species' long-term survival. 

FIF welcomes applications for the $5,000 available in research funding.

 

Download FIF 2021 Research Grant Application

Applications will be accepted through August 31, 2021

2020 Grant Recipient:  

Alexandra DeCandia - Island Fox Microbiome

Previous Research Grant Recipients and other island fox research

Your donations to Friends of the Island Fox

help make this research grant possible