Santa Catalina Island Fox
Progress has recently been made in Santa Catalina Island Fox conservation efforts, leading to the reclassification of the fox from endangered to threatened. Still, there is more to be done!
Physical Traits
- Smallest fox species in the US
- Weight: adult males, 2kg, adult females, 1.88kg
- Body length including head and tail: 59-79cm
- Tail: 11-29cm
- Height at shoulder: 12-15cm
- Underside of tail is rusty color
- Fur color differs among channel islands and differs greatly among individuals, including grey, brown, red, honey
- Molt once a year between August and November – fur fades
- Lifespan: average 4-6 years, up to 15
- Active during the day, primarily forage/hunt at dawn and dusk
- Derived from mainland grey fox
Life History
- Santa Catalina Island’s largest land predator
- Diet: Omnivores
- Eat mice, lizards, birds, berries, insects, cactus fruit
- Ability to utilize a wide variety of food resources increases fox survival chances
- No critical habitat
- Geographical Location: Mainland (LA County), Santa Catalina, San Miguel, Santa Rosa, Santa Cruz
Golden Eagles (top right and bottom center) and peregrine falcons (top right) (US Fish and Wildlife 2020)
Ecosystem Contributions
Main Predators: Raptors
Originally attracted to the Channel Islands by non-native species including feral pigs, Golden Eagles are now responsible for a majority of Island Fox mortalities
Main Prey: Small Rodents
Island Foxes help maintain the balance of mice and skunks in island ecosystems
History: Cultural Significance
Island Foxes were a traditionally honored and respected species by native tribes on the islands, including the Tongva and the Chumash
(Wayne, R.K. et.al. 1991; Coonan, T. J. et.al. 2005; Robinson, J.A. et.al. 2016)
Endangered History
1994:
1300 island foxes on Santa Catalina Island
450 island foxes on San Miguel Island
1999:
100 island foxes on Santa Catalina Island
<20 island foxes on San Miguel Island
2004-2005:
Island foxes are first listed as federally endangered and exist at a critically low population level
From a population of near 0, island fox territories were reestablished at the East End of Santa Catalina Island
60% of island foxes had been vaccinated against CDV
2016-2017:
Island foxes were transitioned from “endangered” to “threatened”
Captive breeding phase of the recovery plan ended, rigorous monitoring plan began
By 2017, approximately 2000 foxes lived on the islands
Endangerment Details:
Between 1994 and 1999, a majority of the island fox population was exposed to canine distemper virus (CDV) around the same time that golden eagles were introduced into the island ecosystems.
During repopulation and recovery, the Western subpopulation was crucial due to its lack of exposure to CDV.
In recovery plans, a population of at least 150 island foxes was to be maintained in each subpopulation in order to reduce mortality due to low biodiversity.
(Coonan, T. J. et.al. 2005; Kohlmann, S. G. et.al. 2005; U.S. Fish and Wildlife 2020)
Recovery Plan
Goal: Increase island fox population size to self-sustaining level and demographic; reduce or eliminate current threats to survival of each subspecies of island fox
Objectives: Goals will be met when quick response to golden eagle predation is available and the demographic of each subspecies exhibits long term stability.
Criteria: Population-based objectives will be met when each subspecies population exhibits no more than 5% risk of quasi-extinction (less than 30 individuals) in a 5 year period. Threat-based objectives will be met when a golden eagle management strategy has been implemented to reduce the threat of golden eagle predation to an average of 2.5% over 3 years and a disease management strategy has been implemented to vaccinate a portion of the population and monitor disease outbreak for early action.
Actions: Increase population size via captive breeding and reintroduction, establish monitoring strategies, and ensure necessary minimum populations for each subspecies.
Total cost: $8.48 million
Schedule: San Miguel, Santa Rosa, and Santa Cruz foxes recovered by 2020, Santa Catalina foxes recovered by 2024
Long Term Conservation: increase island fox education, restore island habitats, and assess threats of vehicles, feral cats, and new diseases such as ear cancer
Stakeholders: the National Park Service (NPS), the U.S. Navy (Navy), The Nature Conservancy (TNC), the Santa Catalina Island Conservancy (CIC), and the State of California
Reflections
I believe that this cost is worthwhile because these foxes are crucial to the ecosystem of protected national park lands and do not exist in any other habitats. If the foxes were present in other habitats or geographical locations, the need to conserve these particular island foxes would be less urgent and the cost would be less justified. Also, if the lands on which the foxes lived were not preserved national park lands, designated as unique and necessary, the conservation of the foxes might be less urgent; however, in order to preserve the national park, the foxes must be conserved, justifying the cost. Island foxes can also be considered an umbrella species because they regulate the survival of smaller animals such as mice and skunks on the islands, making their preservation necessary to the function of the ecosystem as a whole. Finally, though the cost of fox conservation is high, island fox conservation does not impede acquisition of resources such as oil, ores, or natural gas, and therefore poses little conflict with human societal functions.
The future is bright for these foxes. Steps have been successfully taken to ensure fox survival and have down-listed island foxes from endangered to threatened. The recovery plan is now in the monitoring phase, in which detailed plans are in place for monitoring disease, golden eagle predation, and population size and diversity. The threats to the population have been clearly identified and the plans to address them seem to be working. The land managers seem well prepared to handle any crises that are identified during monitoring effectively. Within the next four years, I expect that the Santa Catalina Island fox will no longer be endangered, and within the next 10 years, island foxes will no longer be threatened.
References
Coonan, T. J., Schwemm, C. A., Roemer, G. W., Garcelon, D. K., & Munson, L. (2005, March). Decline of an Island Fox Subspecies to near Extinction. The Southwest Naturalist, 50(1), 32-41.
Final Rule to Remove Island Fox Subspecies on Northern Channel Islands from the Endangered Species List Due to Recovery (2020). U.S. Fish and Wildlife Service.
Kohlmann, S. G., Schmidt, G. A., & Garcelon, D. K. (2005, April 10). A population viability analysis for the Island Fox on Santa Catalina Island, California. Ecological Modelling, 183(1), 77-94.
Robinson, J. A., Ortega-Del Vecchyo, D., Fan, Z., Kim, B. Y., vonHoldt, B. M., Mardsen, C. D., … Wayne, R. K. (2016, May 9). Genomic Flatlining in the Endangered Island Fox. Current Biology, 26(9), 1183-1189.
Santa Catalina Island Fox (2020). In U.S. Fish and Wildlife Service: ECOS Environmental Conservation Online System.
Wayne, R. K., George, S. B., Gilbert, D., Collins, P. W., Kovach, S. D., Girman, D., & Lehman, N. (1991, December). A MORPHOLOGIC AND GENETIC STUDY OF THE ISLAND FOX, UROCYON LITTORALIS. Evolution, 45(8).
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