Island Fox F257 is Back and Beautiful at Middle Age

 

F257 August 2024

Channel Island National Park biologists are on Santa Rosa Island this week capturing island foxes, counting them, checking their health, and updating radio-tracking collars. Biologist Juliann Schamel contacted FIF with great news: Female island fox 257 was captured for the 5th year in a row and she's looking great! Here's Juliann's update:

F257 was born in 2019, and has spent her entire life in her natal area, which overlooks the East Point estuary [as] Santa Cruz Island floats on the horizon.  Every year since 2019, she has gone into traps at our long-term monitoring site at Old Ranch.  She has spent a total of 18 nights in our "island hotel."  Every year, she moves between Trap 1, Trap 11, and Trap 12, which are in a triangle 200 meters apart from each other.

F257 is five years old now, and remains in great health.  She has been monitored with VHF collars throughout her life, and is currently wearing her third collar.  She has Age Class 2 tooth wear.  As an adult, she has fluctuated in weight between 1.8–2.2 kilograms (4–4.9 pounds). 

 

island fox whisker sample

This year, during her health check ... she also contributed samples to microbiome, leptospirosis, and stable isotope research (gut swab, urine, and whiskers).

 

In 2023, she had signs of nursing pups for the first time.  This year she does not show signs of having had pups.  (As pictured, her belly is white.) Data from our long-term monitoring sites has allowed us to document fox recovery to carrying capacity, which was reached in 2020. (What is carrying capacity?) 

 

Since then, the population has displayed density-dependent reproductive suppression (which I think is SO COOL!!!!) - very few pups were weaned in 2021, 2022, and 2023, adult survival remained high, and the total population has remained around 2,500.  Collecting long-term data during this time period has allowed us to document which adult females reproduce and which do not in this high-density landscape (how old are they? what habitat do they live in? how dense are the foxes in their local area?), which will provide further insight into what environmental factors influence fox biology, and how fox ecology in turn influences the landscape.  Old Ranch, where F257 lives, has a high density of adult foxes with high survival, and this area has not produced many pups in the past several years.  With the VHF collar, we will be able to monitor F257's health and status for years to come!

It's been so lovely to see F257 again! - Juliann Schamel

Schamel is not only a fox biologist out on the northern Channel Islands, she's also researching the complex interactions between island foxes and the landscape on Santa Rosa Island. 

 

"Date with a Fox" with Juliann Schamel

More on island fox density

Your Donations funded F257's radio collar and 

vaccinations for rabies and distemper!

She's Back! F257 - an Island Fox with a Story

F257 was true to form in 2023. She was captured during island-wide counting on Santa Rosa Island for the fifth year in a row!

This charismatic female island fox was first captured and radio-collared in the fall of 2019 as a pup of that year. She was collared in the territory where she was born and there were thoughts she might provide additional data on how far female offspring disperse from their parents' territory.

 

She didn't go anywhere. F257 remained in the coastal plain of her childhood. She has been captured each year, not only in the same area, but in exactly the same location. A highly unusual occurrence.

 

Health checks in 2020, 2021, and 2022 found F257 healthy even during years of drought. She even was videoed after receiving her new radio collar. But physical evidence revealed that this healthy female island fox had not become a mother. Island foxes typically have pups in their second year, but they can breed before they are a year old if resources are available. During the 2021–22 drought years, most female island foxes did not breed.

This year F257 approached breeding season as a middle-aged fox–4 years old.

The rainy winter suggested a boom of resources for island foxes. We all waited to see what would happen with F257.

When she was captured in September, F257 showed evidence of nursing pups. 

Island fox females who have NOT been nursing have white bellies.

Females that have been nursing have pink bellies.

F257 has added her genes to the population of island foxes on Santa Rosa Island. We hope she continues to thrive and tell her story.

More on island fox reproduction.

Do You Remember This Fox? It's F257

 

Even with her face covered, F257 from Santa Rosa Island is a stunning island fox. Her coat is lustrous, her weight is good, she looks healthy. The mask/muzzle helps keep her calm during her health check.

You might remember F257 from 2021, 2020, and 2019. 

She received her first health check when she was a pup in July of 2019. In the winter of 2019, she was fitted with her first radio tracking collar.

F257 continues to live in the Old Ranch area on Santa Rosa Island. This is the same area where she was born and first seen.

 

In August, National Park biologists were happy to see F257 during island-wide counting of island foxes. Biologist Juliann Schamel says "[F257] has been captured every summer on the [Old Ranch] grid, and has never shown signs of having reproduced, although she is in good condition/health. She's still quite young and most foxes on Rosa did not reproduce in 2020 or 2021, so this isn't surprising." 

Low rainfall frequently correlates with fewer resources and female foxes tend to have fewer pups or no pups. Santa Rosa Island may also have reached maximum population size. F257 may not be able to find a mate or adequate territory to support having pups. Being single, may also be a choice. She looks great.

You can see from her data sheet that F257s health check and the replacement of her radio-collar took only 12 minutes.

After two and a half years, F257's radio collar needed a new battery. Her collar was replaced and the old collar will be refurbished so it can be used again. In the video below, you'll see F257 be released after her health check.

 

Did you notice F257 looked back at the biologist multiple times. Maybe she recognizes the biologist, too. 

With her radio-tracking collar F257 is helping to monitor island fox survival on Santa Rosa Island. 

Your donations to Friends of the Island Fox fund radio-tracking collars and important research across the Channel Islands.

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.