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| 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).
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| 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.
More on island fox density
Your Donations funded F257's radio collar and
vaccinations for rabies and distemper!
