Friday, December 01, 2017

Fox Foto Friday - Island Fox Pairs


Marty Chin - I took this on my first trip to Santa Cruz Island back in 2011 with the Sierra Club 20's and 30's Group. I spent about an hour watching these rascally young foxes looking for food, playing, and marking territory. Love Friends of the Island Fox and the great work you do.  I met some of your volunteers twice on Earth Days at the LA Zoo.

Thank you Marty for sending in your photo for our Fox Foto Friday. This pair of island foxes is the perfect December image. Right now island fox pairs are taking a break from family life, but around the end of the year they will find a mate or re-establish their pair bond.

Submit your island fox photo to islandfoxnews@gmail.com and be part of Fox Foto Friday.

Friday, November 17, 2017

What Do Brown Boobies Have To Do With Island Foxes?

Have you heard that a seabird called the brown booby (Sula leucogaster) has recently been found nesting on Santa Barbara Island for the first time? 


brown booby beneath western gull; Santa Barbara Island, CA

If you did, you might not have connected this news to island foxes. Brown boobies have historically been residents of Baja and Mexican coastlines. They typically feed on fish species found in warmer waters and are considered a tropical and subtropical species. Channel Islands National Park reports that brown boobies have been gradually moving north since the 1990s. Their occurrence on the Channel Islands coincides with documentation of warmer ocean temperatures along California's coast. The fact that these southern birds are attempting to nest here for the first time is evidence of a healthy marine ecosystem, but also changing local climate. Similarly, our brown pelicans (Pelecanus occidentalis), which were previously only known to nest in California, have been ranging further north. They have attempted to nest along Washington's Columbia River and in the past few years have become summer regulars in southern British Columbia, Canada.


Strong-flying birds have the ability to relocate as temperatures change. Island foxes and the other terrestrial plants and animals of the Channel Islands do not have that option. They will have to adapt to changes in their environment to survive. There are some reports of island foxes breeding and having pups earlier on the southern Channel Islands then documented in the past. Lightening storms brought fire to Santa Cruz this summer and extended drought has challenged some island fox populations.

While the brown boobies are a native coastal species, they have only been occasional visitors to the Channel Islands in the past. Brown boobies are diving seabirds larger than our commonly seen western gull (Larus occidentalis). They are exciting to see, but will their northern movement have an impact on other native species? (video of brown boobies on Santa Barbara Island in 2015 via TheEarthMinute.com)

Are there other, small and less observable species, that are also relocating to the Channel Islands? Will climate roamers bring beneficial diversity or new parasites and disease? 

In this time of global change, monitoring island foxes and their island ecosystem is vital to the species' long-term survival.

Monday, November 06, 2017

Re-examining Island Fox Diet

What do island foxes eat?

Island fox scat with native fruit seeds
It is a common question and examining island fox scat (or poop) has provided some of the best answers. In 2009 a year-long study examined island fox scat over four seasons and across the six islands where they live. New Findings on Island Fox Diet.

The findings from this study, however, were done before multi-year drought impacted vegetation across California and on several islands. Have island foxes shifted their diet to other foods to make-up for the decreased availability of some plant foods or prey species?

Island fox scat with insect exoskeleton remnants
In 2009, island fox populations were recovering on four islands from near extinction and their population numbers were still relatively low. Most fox pairs could establish a territory in an area with abundant resources. Now that the populations have recovered, are island foxes eating a more diverse diet to meet their food needs? Are beetles and insects still the most frequently eaten prey? Have island foxes in marginal territories started to consume other food items? 


In addition to scat, whisker samples can provide evidence of what an island fox has eaten over several months. Whiskers are specialized hairs that grow over an extended amount of time. Trimming an inch or two off the end of a whisker, can provide researchers with information on what a specific individual fox has been eating. Isotopes laid down in the hair shaft document the kinds of proteins and plant matter consumed.


 While we don't think of island foxes eating marine animals, during a limited test study, one individual island fox was found to have isotope markers that signaled it was eating marine proteins, fish or crustaceans. Was this individual unusual?

Research on island fox diet is an on-going project. Biologists in the field counting island foxes on the northern islands were taking whisker samples this year.

Whether it is scat or whisker samples, it is time to add a new chapter to research on island fox diet.

Friday, September 29, 2017

Fox Foto Friday - How Old Is That Island Fox?


How can you tell the age of an island fox?

Biologists used to determine general age by looking at an island fox's teeth. Individuals with worn teeth were thought to be older animals. Island foxes living in dune areas, however, may consume sand while eating insects and crustaceans. Sand wears away the teeth and can make an island fox appear older than it really is.

Most island foxes are in their prime from 2-6 years old. The island fox pictured above no longer has the pricked-up pointy ears of a youngster. His battered right ear has been bitten a few times by other island foxes, a sign that he is an adult with a little mileage. Compare older foxes vs. younger foxes

Some island foxes can have ears torn off in territorial deputes with other island foxes. Island fox missing an ear.

Initially it was believed that island foxes lived 8-10 years in the wild. But ID microchips have provided specific information on individual island foxes. On Santa Cruz Island the oldest documented island fox was a female born in the captive breeding program that lived to be 12 years old. On Catalina Island, numerous island foxes have lived to be 12, while several individuals have neared 13 or 14 years old.

The individual island fox above is probably between 4 and 10. It's hard to guess by appearance alone. His microchip and annually collected health-check data can tell us specific information about his life. Collecting scientific data on island foxes is helping us to understand their lives in greater detail.

Monday, September 18, 2017

Wildfire Can Threaten Island Foxes


Responding to wildfire on the Channel Islands raises a quandary, because there are positive and negative aspects to letting wildfire burn:
  • Fire is a natural element on the Channel Islands. Many native plants depend on fire to open up areas for new growth, to renew the soil, or even jump-start seeds. As omnivores, island foxes depend on diverse and healthy native plants.
  • Fire can provide unexpected abundance for predatory or scavenging animals, including island foxes. Smaller animals may get caught in the fire, while birds and larger animals might escape.
  • Years of drought, however, have created areas with exceptionally dry vegetation and greater than usual build-up of wildfire fuel.
  • Land animals, like the island fox, and some lesser-flying birds, like the island scrub-jay, can not escape a fire burning out of control that might consume an entire island.
  • Santa Cruz Island is home to endemic plants and animals that only live on that one island and nowhere else in the world. If the entire island burned, some of these species might be driven to extinction.
  • The National Park is tasked with protecting historic human cultural artifacts and structures that could be destroyed.
  • People visiting the island can not easily evacuate on their own; they are dependent on sea or air transportation provided by others. The National Park must always consider visitor and staff safety.
Island scrub-jays only live on Santa Cruz Island
When lightning struck Santa Cruz Island during the night of Sept. 10th or early morning of Sept. 11th, all of these factors (and more) had to quickly be taken into account by officials at Channel Islands National Park.
2007 Catalina Island Fire
'Burnie Boots' - Catalina 2007
In 2007, fire raged up canyons and across hillsides on Santa Catalina Island. While only one female island fox was known to be injured in the fire, biologists later discovered that numerous island fox pups were lost to the flames because the fire occurred in spring and many pups were still too young to leave the dens where they were born. Catalina Island Conservancy biologists believe the injured female island fox risked her own life, walking across burning coals, to try and return to her pups in the den.

Wildfire is unpredictable, and in this incidence, the negative threats outweighed the potential positives. U.S. Forestry Service smoke jumpers were called in and they parachuted down to the island to put out the fire.

Fire on Santa Cruz Island 2017 - U.S. Forestry Dept. via Ventura Co. Star
The wildfire was first spotted by a concerned citizen on a boat. Threats to island foxes and the Channel Islands can come in many different forms. Some like disease from domestic dogs or introduced wildlife are similar to lightning, they may initially strike in one place, but the consequences can quickly spread across an entire island. Island foxes need all of us to be as vigilant as the boater who reported the wildfire - one person can make a difference.

Friday, September 15, 2017

Fox Foto Friday

Photo by Douglas E. Welch (http://Douglasewelch.com) June 1, 2013
An island fox (Urocyon littoralis) takes advantage of its natural camouflage to hide among the dry grasses of Prisoners Harbor on Santa Cruz Island.

Find out more about the properties of island fox fur that enhance camouflage and how identifying individual island foxes goes beyond color markings.

Wednesday, September 06, 2017

Tracking An Island Fox

Welcome guest writer Mike Watling. As a certified wildlife tracker and member of Ventura County Wildlife Trackers, Mike shares his expertise in identifying island fox tracks.

Visiting Santa Cruz Island this past winter, I was more excited than usual as it had rained a few days prior to the trip. The miracle of mud, following a rain, provides an excellent medium for studying the tracks left behind by animals. As a naturalist and wildlife tracker, I was looking forward to spending my day carefully observing the minute details of the delicate tracks of the Channel Island fox.

The island fox and its mainland cousin the gray fox are the only fox species capable of climbing trees. The island fox is the island's largest mammal and main predator; the top dog if you will.

Unlike the gray fox, which is primarily a nocturnal hunter, the island fox is active both day and night and can be readily observed foraging for lizards, insects, and fruit that comprise a large portion of its diet. To help conserve energy, foxes will often travel on the roads and trails found throughout the Channel Islands, leaving behind tiny tracks for the observant naturalist to find. 

Like all species in the Canidae family, the fox places its feet on the ground in a manner known as digitigrade. To put it simply, while they are moving, their body weight is being supported by the digits (toes) rather than the entire foot structure. In contrast, humans and bears are plantigrade, meaning the body weight while in moition is being supported by the entire sole of the foot. This characteristic is evident in the tracks left behind.

Consistent with all canids, the island fox has five toes on each forefoot. Toe one, the dew claw, is greatly reduced and located above the carpal pad on the inner leg. Only four toes typically appear in a track. The metacarpal pads, or palm,are fused together to form a larger rounded, yet triangular pad. The space between the toes and the pad, known as the negative space, forms an “H”.

The hind feet have four toes, and like the front, the pads are fused to form a narrow heel pad, which only partially registers in a track.  The negative space forms an “X”.
 
Island fox tracks are small, mostly symmetrical, approximately 1 to an 1 1/4 inches long by 13/16 of an inch wide, with the front track larger than the hind. The two inner toes tend to be close together and are often angled inward towards each other. Often the fur surrounding the foot will leave a visible impression in the track as well. The claws of the island fox are semi-retractable and slightly curved, and may not register. Even in mud, the claws appear very fine if at all. 

 
Island foxes generally move throughout their territory in a slight under-step trot. Having the shortest leg-to-body ratio of all the wild canines, the resulting track pattern is such that the front toes are visible ahead of a complete hind track.

While hiking the Channel Islands, take time to look closely on the side of the trail where you’ll likely encounter the tracks of the island fox, as well as other island inhabitants.  Quietly observe the entire area; look around for other pieces of evidence and you may be able to determine what the animal was doing.  Give pause, and for that moment, walk with the Island Fox. - Mike Watling

Tuesday, August 08, 2017

Visiting the Island Fox on Santa Cruz Island

What is like to visit the island fox at home? Walk along with our guest blogger - Douglas E. Welch

Island Journal - My First Visit to Santa Cruz Island


It took me over 25 years living in California to make my first visit to Santa Cruz Island. The Channel Islands have always intrigued me, but they seemed so difficult to visit.

Finally, the day arrived when our entire family boarded a boat for Santa Cruz Island. This was a trip sponsored by the Friends of the Island Fox. They took care of organizing our transport and acted as interpreters for all we hoped to see that day. The sun was shining brightly when we left Ventura Harbor, but as we got closer to the island a deep fog set in. Santa Cruz had to be out there somewhere, but we also could have been in the middle of the Pacific for all we knew. It was only by looking at my gps position on my iPhone that I knew we had to be close.


Suddenly a pier faded into view and then a shoreline and then Santa Cruz Island’s mountains. Within a few minutes, we were on dry land again and beginning our exploration of this very wild portion of California.


Because of the island’s isolation, everything looked familiar–but different. Of course, the island foxes only inhabit the Channel Island; they were completely new to me. It was amazing to see something so rare (and so darn cute) up close. They are smart, too. One fox even tried to raid a backpack while its owner napped nearby. Something you always need to be on-guard about when you visit the islands.



The flora and bird life were slightly different too. The giant coreopsis takes on huge proportions when compared to their mainland counterparts. What looked similar to a mainland scrub-jay turned out to be an island scrub-jay, also endemic to the islands. Again, familiar–but different.

For me, another unique feature of the island was the sound the cobbled rocks made as the surf washed them first onshore and then retreated. The stones rolled back and forth clinking and clunking like a stone xylophone. I watched and listen to that sound for quite a long time as we waited to board our boat home. I was amazed at its musicality.



Since this visit, I now take every opportunity to visit the Channel Islands. It is always an amazing day of unique flora and fauna and striking scenic vistas that seem to faraway, but are right here in our own backyard. - Douglas E. Welch  

Other Island Journal entries:
 
 
 

Monday, June 19, 2017

Island Fox Behavior in 2017

courtesy of K. Schafer
In 2017, visitors to the Channel Islands have the opportunity to see something that was rare just a few years ago: wild island foxes interacting with each other.

When island foxes faced extinction in 2000, surviving individuals were brought into captive breeding facilities. From 2000-2006, seeing an island fox was a momentous occasion. Since 2008, all island foxes have been returned to the wild (with the exception of a few in mainland zoos). As the populations recovered across the islands, the opportunity to see island foxes hunting and interacting with each other has increased. (seeing island fox behavior on Santa Cruz Island 2015).

Witnessing interactive behavior between island foxes is a gift provided by the successful recovery of this once endangered species. Here are some of the behaviors we saw in late May:

Vocalization: Yes, island foxes vocalize. They bark, growl, and pups make soft whimpering and eecking sounds. 

  • Barks are typically high pitched and evenly spaced. Barks may be repeated multiple times. In the distance, we heard an island fox bark eleven times in a row. This vocalization is used to warn an interloper that they have trespassed on an individual's territory. Island foxes may bark at each other or, occasionally, at humans. If an island fox barks at you, you are too close. Hear an island fox barking.
  • The Growl of an island fox is low and soft. Typically this sound is used to warn off another island fox that has approached too close. We saw an island fox curled up sleeping by the side of a dry creek bed. A second island fox approached it, coming within five feet. The fox laying down, growled at the approacher. The second fox stopped, turned around, and went the other direction.
  • Pup Sounds are typically only heard by parent foxes. The following pup vocalizations were recorded at the Santa Barbara Zoo from a pup that was abandoned by its parents. Hear island fox pup vocalization

Aggressive Territorial Behavior: Island foxes are very territorial. (Territory size) Living on an island with limited resources means quality territory is vital to survival. A pair of island foxes mates for life to protect their territory and the resources needed to feed themselves and their offspring. Challenges over territory can occasionally lead to aggressive behavior.

  • Vocalizations (see above) are used to warn other foxes and avoid physical confrontation.
  • Chasing can occur when an island fox intrudes into the territory of another island fox or pair. We saw one adult island fox chasing another adult island fox out of the campground area.
  • Physical Altercations can occur between island foxes, especially over territory. Island foxes with floppy ears are typically older individuals who have had altercations with other island foxes. The cartilage of the external ear can be damaged by bites or twisting from other foxes. Over time, repeated damage leads to ears that flop down or may even be torn off. Bites to legs are also frequent injuries. Limping island foxes are often individuals that have been bested in a squabble.
island fox with damage to ear caused by another island fox
parent island fox with two pups

Affiliative Behavior: Island foxes are family oriented and pair bonded. They demonstrate caring and friendly behavior to family members. Female offspring remain in the same area as their parents and on occasion friendly behavior may occur between adult offspring and their parents or siblings.

  • Care for Pups includes teaching pups to hunt and find food. It is not unusual during the summer to see an adult island fox leading a younger island fox around, showing them where to find specific food resources. Parents lick pups to groom them and also accept playful pounces from youngsters. Parents may discipline a misbehaving pup with a warning snarl, lifting the lips to show the teeth. The pup will show submission by lowering the head and body, flattening the ears, and licking the chin of the parent. Island Fox Pups
  • Familial Recognition or recognizing family members is a behavior that is being seen more as fox families build generations. This May we saw a young adult island fox (1-2 years old) approach an elder island fox sleeping curled up along the dry creek bed. The younger fox came right up to the older fox and sniffed it. The older fox did not growl or demonstrate any aggressive behaviors and the younger fox did not try to chase the old fox or intimidate it in any way. This interaction was completely different from the aggressive behavior seen between two other adults on the same day (see The Growl above). Do island foxes continue to recognize family members throughout their life and maintain friendly behavior toward them? (See - Two adult island foxes meet) This is definitely an area that needs further research. 
island fox pup shows submissive behavior to parent
It is exciting that there are questions to be researched regarding island fox behavior. If we had lost the island foxes on Santa Cruz, Santa Rosa, San Miguel, and Santa Catalina Islands seventeen years ago, we would have also lost the opportunity to know this species better, to understand how it behaves, and how island isolation has changed its behavior from the mainland gray fox.