Tuesday, May 04, 2021

Distemper Outbreak in Long Beach Raises Threat to Island Foxes

courtesy of M. Baffa

April 15, 2021 the City of Long Beach issued a press release "Animal Care Services Reports Distemper Outbreak." The city reported that "38 raccoons and at least one skunk" had been found with the highly transmissible disease: canine distemper virus (CDV). 


This is the kind of situation that led to the serious decline of the Santa Catalina Island fox between 1998–2000. A wild raccoon infected with canine distemper virus was unknowingly transported to the island. Canine distemper virus killed 90% of the Catalina Island foxes within months and necessitated a multi-year effort to recover their population.

CDV can easily be passed from wildlife to pet dogs through direct contact or the sharing of food or water bowls. You can help protect the island fox and your pets. Vaccinate your pet dog against canine distemper virus. A vaccinated pet is protected and stops transmission from continuing. When there are high levels of CDV on the mainland, the threat to island foxes magnifies.


There are currently over 2,000 individual island foxes on Catalina Island. CDV is especially deadly to puppies and island fox pups. Island fox pups were born across the islands in April; they will be especially vulnerable for the next few months.

Friends of the Island Fox is raising funds to assist the Catalina Island Conservancy in vaccinating 300–350 island foxes on Catalina Island this summer. That is still only around 15% of the population. Vaccinating island foxes is the best chance for protection.

There are several months between now and when island foxes will be vaccinated. You can help protect island foxes from this heightened disease threat:

  • Vaccinate your dog against canine distemper
  • Do not feed wildlife, especially in harbor or port areas
  • Dispose of trash in secured bins so wildlife can not access it
  • If you have a boat, or know someone who does, always be aware of wildlife that may be hiding on board. If you detect a raccoon or other animal, return to port, DO NOT continue on to Catalina. Be wary of transporting any wildlife or feral animals to Catalina or any of the Channel Islands.
  • Consider donating to FIF - a $20 donation will vaccinate an island fox against canine distemper virus and rabies.


Island foxes need all of us to be vigilant and stop the spread of this current CDV outbreak.

Your donation will help vaccinate island foxes against deadly canine distemper virus. 

Friday, April 23, 2021

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

Friday, April 16, 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
 


 

Friday, April 09, 2021

Island Foxes On Facebook

Friends of the Island Fox is migrating!


OK, we're moving to a new Facebook home.

FIF has been on Facebook since April 2011. We've changed, Facebook has changed, and island foxes on Santa Rosa Island have gone from a population of 449 to an estimated 2,427.

We want to keep telling you about island fox conservation successes!

If you follow us on Facebook, we hope you'll migrate to: 

FIF's New Facebook page

 @FriendsoftheIslandFox

The old page will no longer be updated. 

We're expanding our horizons, just like this island fox spotted last week on a mountain top on Santa Rosa Island.


Spread the news to your friends.

You can also follow us on Twitter @ifoxtweet or sign-up for our bimonthly e-newsletter.

Friday, April 02, 2021

Fox Foto Friday - Island Foxes in Washington D.C.?

What smells like an island fox? Came from an island fox? But is contained on the tip of a cotton swab? A sample of island fox microbiome.

Island fox being swab with cotton swab

Friends of the Island Fox recently heard from FIF 2020 Research Grant recipient, Alexandria DeCandia, Ph.D.

DeCandia wrote "I wanted to let you know that microbiome samples from all six islands have arrived on the east coast :)" Swabs taken from island foxes during health checks have been transferred to a lab in Washington D.C. She added, "I'm very much looking forward to the next steps of this research!"


FIF's Research Grant is funding the DNA analysis of the swabs to get a picture of the biodiversity of microbes living on and in island foxes.

What Is She Looking For?

DeCandia's research is cutting edge science. Her early analysis of Catalina Island foxes led to some important findings on the possible relationships between bacteria in island fox ear canals and a tendency toward extreme immune system response to ear mites. This next stage of research builds on that work.

Maintaining healthy island foxes across the islands requires greater in depth understanding of their health, diet, position in the ecosystem, and interactions with other species, including humans. 

Friends of the Island Fox invests in research to invest in the island fox's future. Applications for the FIF 2021 Research Grant will be available April 15, 2021.

Friday, March 19, 2021

Is That An Island Fox? Identifying North American Foxes


Fox species overlap in many parts of North America, which can make it difficult to distinguish one species from the next. In California alone, there are four fox species:

The last three occur only on the mainland. If you are fortunate to see a small to medium canid in the field, you should ask yourself a few questions to aid in identification:

fox silhouette


 

coyote silhouette

1. Is it a coyote or a fox? 


Coyotes now inhabit most of North America, but they are typically larger than foxes and appear more dog-like with a larger face. The coyote tail is also shorter for their body than a fox's. While most foxes have distinct color markings to aid in identification, coyotes do not.


If it is a fox: 

2. Start with the tip of the tail:

White tail tip: Probably a red fox. Even if the fur coloring is not red or cinnamon, a fox with a white-tipped tail is a red fox.  The image to the right shows a "silver fox," an almost black-colored fox with white-tipped guard hairs beside a red fox. Both show a white tail tip. 

The silver fox is a color phase of the red fox (Vulpes vulpes). Most foxes used in the fur trade are red foxes. They are bred for various colorations. (FIF's red fox pelts are used in education. The silver fox pelt was rescued from a 1940s coat and the wild red fox was a car strike victim in 2005.)

 

gray fox; ancestor of the island fox

Black tail tip:

With a black stripe all the way down the back - you are looking at a gray fox. (If you are on the Channel Islands, it's an island fox.)

island fox on Catalina Island

 

kit fox; courtesy of K. Schafer
 

Just a black tail tip: Consider your location.

The Gemini foxes, the kit fox and the swift fox, seldom overlap in range. If you are located in parts of New Mexico and adjacent parts of Texas, big ears will separate the kit fox from the swift fox. In general, understanding the habitat where you see the fox will provide a clue as to the species you're observing.

No, definitive tail tip coloration: Arctic fox

Arctic foxes are easy to identify by their white coat in winter or their compact body size with small rounded ears and no contrasting marks on the tail.

Use this downloadable Identifying the Foxes of North America chart to help you know your local foxes. 


In this series of posts, we only touched the basics for each of the species covered. A list of research used in writing this project can be found at the end of each post. These resources are a great starting point for more information about the foxes that may live in your area. In addition, reading the abstracts of research articles provides wonderful insights into the latest information regarding a particular species. While the thought of wading through heavy scientist language may make your head spin, the abstract's concise language will slow that spin, allowing you the opportunity to glean useful information to assist in the better understanding of the fox you're interested in. It will also help sort fox fact from fiction.

Thank you to FIF Board Members - Mike Watling and Lara Brenner for this series on North American Foxes.

Series installments:

How is the Island Fox Unique?

Red Fox: Life on the Edge

Gemini Foxes: Kit Fox and Swift Fox

Arctic Fox: Fox of the Tundra

The Island Fox's Origin - The Gray Fox

 


Friday, March 12, 2021

The Island Fox's Origin - The Gray Fox

Gray fox (left) with two island foxes at CALM Zoo, Bakersfield CA

In previous posts we've introduced the red fox, the most widely distributed land carnivore on the planet, kit and swift foxes (the Gemini foxes), who inhabit the arid regions of North America, and the arctic fox, a true species of the north. In this installment of Foxes of North America, we conclude with the progenitor to the island fox: the gray fox.

island fox
 

As we've previously discussed on the Friends of the Island Fox website, the island fox descended from the gray fox (the island fox's "progenitor" or ancestor) between 7,000–9,000 years ago. In evolutionary time, that's relatively recent. When you examine the canid family tree, you'll find that the gray fox and its predecessors have been continuously inhabiting southern North America and Central America since the middle Miocene (10 million years ago). The genus Urocyon is the most primitive living canine lineage, closest to the origin of all canid species.

 

 

gray fox, Southern CA

Gray Fox: The Fox of the Forest

Gray foxes are commonly associated with deciduous or mixed coniferous forests. In contrast to the red fox, which prefers forest openings–meadows and farmlands–the gray fox prefers the cover of woodlands. Forested habitats allow this inconspicuous fox to elude predators in a most unusual way for a canid: it climbs trees! 

One set of traits retained from the gray fox's early divergence from other carnivores, (and one that other canids have lost) are its highly re-curved, semi-retractable claws and rotating forearms. These feline-like qualities allow a gray fox to hug trees much the same way a cat does. The gray fox's relatively short leg to body ratio lowers its center of gravity, aiding in balance and making it easier to use trees as a means of escape and to forage for bird eggs and fruits. (Island foxes have inherited this climbing ability.)

Found from southern Canada to northern Columbia and Venezuela, the gray fox is the only fox species to range across both North and South America. Gray foxes are absent from the northern plains and Rockies, as their short legs make it difficult to navigate areas with deep snow. In Southern Canada, gray foxes live in coniferous forests, where dense foliage may help mitigate the effects of heavy snowfall.

gray fox, photo courtesy of Jim Carretta
 

The scientific name for gray foxes, Urocyon cinereoargentus, breaks down as follows: Urocyon is Greek for "tailed dog" and cinereoargentus translates to "silvery gray," which accurately describes this handsomely dappled fox. (Island fox's scientific name.) Its underside is a cinnamon-rufous color and there is white fur on the face, throat, belly and hind legs. The tail has a black tip, which helps distinguish it from the red fox, whose tail is white tipped. There are distinct black spots on either side of the muzzle. The long bushy tail makes the gray fox appear larger than it really is. In general, they stand about 14 inches at the shoulder; weigh from 7–13 pounds and are 31–44 inches long from head to tail. (Compare to the island fox)

The gray fox is the most omnivorous of the wild canids. Just like the island fox, their varied diet consists of small mammals, birds, fruits, nuts and invertebrates such as Jerusalem crickets and grasshoppers. Their diet varies throughout the year based on prey availability, which allows them to adapt to changing environments.

island fox family allogrooming

While mostly solitary, gray foxes do spend time in pairs or in small family groups through out the year. More than any other fox species, gray foxes can be seen allogrooming, which is when individuals socially groom each other and their pups to remove ticks and pests. If you visit a Channel Island, you can see that this trait has been carried over to island foxes, as they are often observed grooming each other.

The gray fox's tendency to prefer areas with thick tree coverage makes this elusive species the least studied of the North American foxes. Overall, the gray fox population is healthy, and habitat loss doesn't appear to be impacting the species for now. Farmers who raise poultry feel that gray foxes are pests, but biologists claim this threat is overstated. On the contrary, gray foxes provide a benefit to humans by keeping rodent populations in check.

Indigenous peoples realized the value of their neighbor the gray fox and thus began a relationship that would lead to the evolution of the island fox.

Previous installments:

How is the Island Fox Unique?

Red Fox: Life on the Edge

Gemini Foxes: Kit Fox and Swift Fox

Arctic Fox: Fox of the Tundra

References

Cyper, B.L. 2003. "Foxes (Vulpes species, Urocyon species and Alopex lagopus)." In Wild Mammals of North America: Biology, Management, and Conservation, 2nd edition by G. Feldhamer, B. Thompson, and J. Chapman (eds), pg 511–546. Baltimore: Johns Hopkins University Press.

Elbroch, M. and K. Rinehart. 2001. Behavior of North American Mammals. pg 105–111. Peterson Reference Guides.

Henry, J. D. 1996. Living on the Edge, Foxes. Minocqua, WI: Northword Press.

 


Friday, March 05, 2021

Comparing the Island Fox and the Arctic Fox; The Fox of the Tundra

Santa Rosa Island fox, courtesy of NPS
 

In this installment of Foxes of North America, we'll look at the Arctic Fox. While the island fox lives on coastal islands that rarely experience a hint of snow, the arctic fox is a true species of the North and has adaptations that help it survive the harsh conditions of the polar regions.

Arctic fox; courtesy of Colby Brokvist: ColbyOutdoors Photography

Arctic Fox; The Fox of the Tundra

Tundra comes from the Finnish word tuntri, meaning treeless plain. The tundra is noted for its permafrost landscapes, extremely low temperatures, windswept plains, little precipitation and long dark winters. Yet, the arctic fox lives and reproduces successfully in this seemingly inhospitable environment. In North America, the arctic fox is found from western Alaska east across northern Canada. The arctic fox is a large North American fox species, weighing approximately 12 pounds.

Arctic fox; courtesy NPS
To survive extremely low temperatures that regularly reach -50 degrees F, the arctic fox has thick fur with two undercoats. This adaptation provides excellent insulation. (Compare to the island fox's fur.) A short muzzle, short ears and legs, as well as a rounded, compact body with a big bushy tail, also reduce heat loss. Arctic foxes have a special counter-circulating blood system that acts as a heat exchanger to cool, rather than warm, the blood flowing to their feet. Having cooler blood at their feet means less heat will be lost to the surrounding surfaces, thus requiring less energy for the fox to stay warm in frigid temperatures. In the summer, arctic foxes shed their long white coat and instead grow short, dark gray to bluish-brown fur.

Arctic fox in summer coat; courtesy NPS

The scientific name for the arctic fox is Vulpes lagopus. Vulpus is Latin for fox, while lagopus is Greek for "hairy foot". This is an accurate description of the fox's thickly furred pawpads; a trait also characteristic of rabbits and hares.


The tundra ecosystem has a simplified food web, because not many species can survive the harshness of the winters. For that reason, the diet of the arctic fox is less diverse than that of other fox species. Arctic foxes are capable predators of small prey, such as lemmings and voles. Individuals living along the coast take advantage of seabird populations, hunting birds and eggs. They also forage other available marine resources. Arctic foxes frequently follow polar bears and scavenge their leftover scraps. Arctic foxes are comfortable foraging on the pack ice as well. These winter weather foxes use the permafrost as a natural refrigerator to cache food in years of abundance for times when food is scarce.

Arctic fox; courtesy of Sean Beckett

Arctic foxes pair up in February and March and mate in April, which is late compared to their southern canid counterparts. (Island fox pups are born in April.) Arctic fox kits are typically born in May or June. They can have as many as 19 pups in a single litter. Extremely large litters of up to 22 kits have been observed. That's the largest litter size in order Carnivora! However, the average number of pups varies by local prey abundance and geographical area. More typical litter sizes for arctic foxes are 6–9 pups in inland areas and 3–6 pups in coastal populations. To handle such large litters, female arctic foxes have evolved 12–14 teats. Arctic foxes use dens primarily during the pup season (like island foxes). They build their dens in sandy soils where they can dig 2–3 feet before reaching the permafrost. Arctic foxes also make snow dens during blizzard conditions.

The fox of the tundra is an elegant creature that has adapted to survive in extremely cold environments. Arctic fox populations in North America are healthy and stable, so this species is not listed as threatened or endangered. That doesn't mean the foxes are without challenges. Red foxes have been expanding their range northward as a result of the warming climate, driving the arctic fox deeper into the polar regions. When red foxes encroach on arctic fox territory, the more aggressive red fox wins out. The extreme conditions of the northernmost arctic regions may limit the range expansion of the red fox, thus giving the arctic fox its best chance for long-term survival.

In the final installment of Foxes of North America, we will concluded with the progenitor of the island fox, the gray fox.

Series installments:

How is the Island Fox Unique?

Red Fox: Life on the Edge

Gemini Foxes: Kit Fox and Swift Fox;

The Island Fox's Origin - The Gray Fox

References

Cyper, B.L. 2003. "Foxes (Vulpes species, Urocyon species and Alopex lagopus)." In Wild Mammals of North America: Biology, Management, and Conservation, 2nd edition by G. Feldhamer, B. Thompson, and J. Chapman (eds), pg 511–546. Baltimore: Johns Hopkins University Press.

Elbroch, M. and K. Rinehart. 2001. Behavior of North American Mammals. pg 105–111. Peterson Reference Guides.

Henry, J. D. 1996. Living on the Edge, Foxes. Minocqua, WI: Northword Press.

 

Friday, February 26, 2021

Gemini Foxes: The Kit Fox and Swift Fox

Santa Cruz Island fox

In the first installment of Foxes of North America we introduced you to the beautiful and intelligent red fox, a fox that prefers to live on the edge and is very different from the island fox.

Here we'll take a quick look at the kit and swift foxes. Don't be fooled by their general appearance–they are not island foxes.

According to J. David Henry in his book Foxes: Living on the Edge, "The kit fox and the swift fox are the Gemini foxes of North America," because they share many physiological and morphological similarities. Kit and swift foxes inhabit the arid regions of North America and are adapted to habitats with relatively open vegetation.

 

Kit Fox, photo courtesy of CA Fish & Wildlife

Kit Fox

Kit foxes are native to the desert and semi-arid shrublands and grasslands of the southwestern US, including parts of Oregon, Colorado, and northwestern Mexico. They are a small fox species with a slender appearance, 5 pounds on average. Their coat is grizzled to tawny gray with buffy highlights on the neck, sides and legs. Their face has a typical "foxy" appearance, except for their ears, which are much longer than those of any other North American canid. This adaptation may help them dissipate body heat in the desert and could help them hunt insects and mice. To protect their feet from the hot sands, kit foxes have considerable hair between the pads, forming a kind of "sand shoe." Kit foxes are often confused with gray foxes because their ranges overlap, but kit foxes can be distinguished by the lack of a black ridge running the length of the tail as well as by their large ears.

The scientific name is Vulpes macrotis, which translates to "big eared fox."

San Joaquin Kit Fox, photo courtesy Tory Westall, ESRP - CSU Stanislaus

Kit foxes are opportunistic foragers that rely heavily on rodents and insects for sustenance. Kangaroo rats, pocket mice, and ground squirrels are common rodent prey. Like island foxes, kit foxes also consume beetles and grasshoppers. Kit foxes are also known to consume rabbits, birds, reptiles, and a variety of non-insect invertebrates

A unique feature of both the kit fox and the swift fox is the continuous use of underground dens throughout the year. Other canid species, including the island fox, use underground dens only during pup season. The Gemini Foxes clump their dens in suitable habitat and use them to provide critical protection from predators and shelter from extreme temperatures in desert summers and northern winters.

The San Joaquin subspecies of kit fox (V. macrotis mutica), which is restricted to the San Joaquin Valley and adjacent valleys in California, is currently listed as endangered under the Endangered Species Act. The kit fox is also listed as endangered by the State of Colorado and as threatened by the State of Oregon. The most serious threats include habitat loss and declining habitat suitability due to invasion of non-native grasses.

Swift Fox, photo courtesy K. Schafer

Swift Fox

Swift foxes primarily occur in the short and mixed-grass prairies from New Mexico and Texas north to southern Canada. Similar in size and appearance to the kit fox, the swift fox is pale yellowish-red and grey, with a thick grey stripe down its back that extends to its black-tipped tail. Its underside is lighter in color, and it has black patches on either side of its muzzle. You can distinguish swift foxes from kit foxes by the swift fox's smaller and rounder ears. Also, the swift fox's tail is shorter in relation to its body size than that of the kit fox.

Their scientific name is Vulpes velox, which simply translates to "swift fox."

 

Swift Fox, photo courtesy Gordon Court
 

Swift foxes are resourceful foragers, with a varied diet that includes small mammals, such as prairie dogs, birds, insects, plants and carrion. To reduce risk of predation by coyotes, swift foxes avoid areas with high prey density, such as areas of high plant diversity. They prefer open habitat where visibility is greatest.

Once abundant throughout their range, swift fox populations began to decline in the late 1800s due to rodent and predator control programs and the plowing of prairie into cultivated crop fields. As a result, the species is currently recognized as a species of conservation concern over much of its range. In Canada, the swift fox was gone or extripated by the 1930s. However, in 1983, a privately run program began breeding swift foxes in captivity in the US so that they could eventually be reintroduced back into the wild in Canada. Experts from this captive breeding effort provided advice for the captive breeding of island foxes in the early 2000s. While swift foxes are still classified as endangered, the swift fox's return is one of the most successful species reintroduction stories in Canada, just as the island fox's recovery is hailed as a success in the US.

Coming up next is the Fox of the Tundra: Arctic Fox

Series installments:

How is the Island Fox Unique?

Red Fox: Life on the Edge

Arctic Fox: Fox of the Tundra

The Island Fox's Origin - The Gray Fox

For additional information on the San Joaquin Kit fox visit: https://www.facebook.com/groups/friendsofthesjkf

References:

Butler, Andrew R., Kristy L.S. Bly, Heather Harris, Robert M. Inman, Axel Moehrenschlager, Donelle Schwaim, and David S. Jachowski. May 22, 2020. "Home range size and resource us by swift foxes in northeastern Montana." Journal of Mammalogy, vol. 101, (3), pg 684–696. Accessed at: https://doi.org/10.1093/jmammal/gyaa030

Cyper, B.L. 2003. "Foxes (Vulpes species, Urocyon species and Alopex lagopus)." In Wild Mammals of North America: Biology, Management, and Conservation, 2nd edition by G. Feldhamer, B. Thompson, and J. Chapman (eds), pg 511–546. Baltimore: Johns Hopkins University Press.

Elbroch, M. and K. Rinehart. 2001. Behavior of North American Mammals. pg 94–100. Peterson Reference Guides.

Harris, Heather (ed). July 2020. Swift Fox Conservation Team Report for 2017–2018. Montana: Montana Fish, Wildlife & Parks Glasgow.

Henry, J. D. 1996. Living on the Edge, Foxes. Minocqua, WI: Northword Press. 

Kelly, Erica C., Brian L. Cypher, and David J. Gemano. 2019. "Temporal variation in foraging patterns of Desert Kit Foxes (Vulpes macrotis arsipus) in the Mojave Desert, California, USA." Journal of Arid Environments, vol 167, pg 1–7. ISSN 0140-1963.

Meaney, C.A., M. Reed-Eckert, and G.P. Beauvais. August 21, 2006. Kit Fox (Vulpes macrotis): a technical conservation assessment. USDA Forest Service, Rocky Mountain Region. Accessed at: http://www.fs.fed.us/r2/projects/scp/assessments/kitfox.pdf 


 

 

Friday, February 19, 2021

Not All Foxes Are The Same - Red Fox vs. Island Fox

Santa Cruz Island fox
Foxes are small- to medium-sized members of the dog family that are found throughout the world. In North America there are six species of fox: Red Fox, Gray Fox, Kit Fox, Swift Fox, Arctic Fox, and of course, the Island Fox. Foxes are the smallest of the North American wild canids, the others being wolves and coyotes. Foxes are very intelligent and adaptable. They occupy varying landscapes across the continent from the vast Arctic tundra to the desert scrub land of the American southwest. From the wind-swept prairies to the boreal forests, the foxes of North America have carved out a niche as specially adapted predators of small prey. 

In the first of a multi-part post on different foxes, we'll introduce you to the Red Fox.

 

European red fox

 
Life on the Edge: Red Fox

The red fox is the most widely distributed land carnivore on the planet, with a range covering more than 28 million square miles. By contrast, the San Miguel Island fox has a very small range: only 24 square miles. Red foxes occupy five of the seven continents, including Australia, where they were introduced by English settlers in the 1800's. Only South America and Antarctica are free from these adaptable animals.

The scientific name for the red fox is Vulpes vulpes, the "fox's fox," which is fitting since most people conjure up an image of the red fox when asked about foxes. (Island fox's scientific name.) The presence of red foxes all over the world has led to their appearance in pop culture and folklore as people are readily drawn to this beautiful and cunning creature. More than any other canid, the red fox has received positive representation in literature and film. Aesop's Fables contain numerous tales of foxes. Disney's The Fox and the Hound tells the story of two unlikely friends, a red fox named Tod and a dog named Copper. To indigenous tribes of North America, the fox is a spiritual animal with different meanings across cultures–from a clever trickster to being associated with intelligence and wisdom.

Tod fox from Disney's The Fox and the Hound
 

Red foxes are the largest of the North American fox species, with a long, bushy tail, a narrow pointed muzzle, and thick soft fur. Their legs are slender with black fur covering the feet, nose, and the back of their erect, pointed ears. The coat of the upper body, head, and tail are bright red to yellowish-red. The tip of the tail is white. Adults are approximately 36–42 inches in total length and their tail accounts for slightly more than one-third of their length. Most adults weigh 10–11 pounds, as much as three times the size of an island fox.

Sacramento Valley red fox; photo courtesy Ben Sacks/UC Davis

Red foxes prefer habitat along edge environments where two habitat types meet, such as the intersection of open meadows and woodlands. In the west, red foxes are primarily found in higher, sub-alpine elevations. In California there are two native sub-species, the Sierra Nevada red fox and the newly described Sacramento Valley red fox. These two native red fox populations are small and geographically isolated (like being on an island). The study of island fox populations has played an important role in helping biologists evaluate the vulnerability of these red foxes to survive into the future.

Red foxes thrive near human settlements, most likely due to the protections humans provide against the foxes main predators: coyotes, bears, and mountain lions.

Red foxes are primarily active at twilight and night, although they may be seen during the day when foraging to feed their young. While omnivorous, their diet consists primarily of rodents, including voles, pocket gophers, and deer mice, as well as cottontail rabbits, jackrabbits, and snowshoe hairs. Like island foxes, red foxes readily eat fruits when they are in season. In some areas, fruits make up 100% of their diet! They commonly consume blueberries, blackberries, and raspberries, as well as apples, grapes, and even acorns.

Like many canids, North American foxes are basically monogamous, and the red fox is no different. Mating occurs between December and April. Pups are born between April and May. (Similar to island foxes.) The typical litter size is 3–6 pups. The male initially participates in feeding and rearing the kits, but moves on as the kits mature.

Red foxes are an adaptable and successful species. They have been extensively studied and their populations are stable apart from the two California sub-species. These beautiful animals extrude the cuddle factor more than any other fox species. (Well, except maybe island foxes.)

San Clemente Island fox
How is the Island Fox Unique?

Coming up next: Gemini Foxes: Kit Fox and Swift Fox;

Series installments:

How is the Island Fox Unique?

Gemini Foxes: Kit Fox and Swift Fox

Arctic Fox: Fox of the Tundra

The Island Fox's Origin - The Gray Fox

 

References:

Cyper, B.L. 2003. "Foxes (Vulpes species, Urocyon species and Alopex lagopus)." In Wild Mammals of North America: Biology, Management, and Conservation, 2nd edition by G. Feldhamer, B. Thompson, and J. Chapman (eds), pg 511–546. Baltimore: Johns Hopkins University Press.

Elbroch, M. and K. Rinehart. 2001. Behavior of North American Mammals. pg 105–111. Peterson Reference Guides.

Henry, J. D. 1996. Living on the Edge, Foxes. Minocqua, WI: Northword Press.

Saunders, D. A. 1988. "Red Fox: (Vulpes vulpes desmarest)." In Adirondack Mammals, pg 216. New York: State University of New York, College of Environmental Science and Forestry.