They have made themselves famous on the Facebook campus, even earning themselves their own Facebook page. They've also made a splash on the Google campus. Gray foxes are right at home around the tech-hubs of Silicon Valley as well as around the urban centers, residential neighborhoods, parks and pretty much anywhere that has enough cover for hiding during the day and enough rodents and other prey for meals in the evening.
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Even though they are widespread across much of the United States and down through Mexico to the Southern parts of Central America, surprisingly little is actually known about the gray fox. It often happens with common species: When they're everywhere, and their populations aren't experiencing any notable rise or the decline, we tend to ignore them on a scientific level.
But that's not the case for Bill Leikam, nicknamed "The Fox Guy," who has been watching local gray foxes for the last five years and documenting their behavior. He founded the Urban Wildlife Research Project (UWRP) to better understand what role gray foxes have in the area and, importantly, what influences and challenges living in an urban habitat presents the species.
Gray foxes are a small canid species, about the size of a house cat. (Photo: Jaymi Heimbuch)
Making room for urban gray foxes
The gray fox is a small member of the canid family. It is the cat-sized cousin to coyotes, wolves and domestic dogs. It is cat-like in more than just size: The species is one of only two canids that can climb trees, and the gray fox can sprint up a tree and navigate its boughs as well as any feline. The behavior works both for escaping predators like coyotes, as well as for catching prey like squirrels and birds.
The gray fox has been around for at least the last 3.6 million years, likely longer, and the species has seen its fair share of change. It has been able to adapt to a wide range of habitats, but it is only in the last century or so that it has had to adapt to living around, and in, large cities. The species has been amazingly successful in the urban setting but there are still problems that seem to pop up, from a high frequency of car strikes to DNA bottlenecks that happen when a population of foxes is stuck in a tough-to-navigate corridor of an urban area and few new foxes can get in or out easily.
That's where Leikam comes in. With his daily monitoring of the famous foxes living in an urban area of Palo Alto, Leikam has uncovered interesting behaviors and pinpointed several issues of concern for the health of the species, including the need to connect and enlarge the wildlife corridors around the Bay Area to allow species like the gray fox, coyotes, bobcats and others to move safely between San Francisco Bay and the Santa Cruz mountains.
“What is the size of your survey area, in miles?” I asked as I tagged along with Leikam one afternoon during one of his twice-daily surveys.
“Miles? Oh no, it’s acres.”
Leikam currently watches a total of about 12-13 foxes in two small areas that total perhaps 6 acres. The population has fluctuated over the years, and just last year there were a total of 27 adults and pups combined that Leikam monitored. The two main habitats for these foxes are situated along a creek and next to buildings, facing each other across a marsh. The foxes hunt within the marsh and rest in the brush and scrub closer to the buildings. It was near one of these areas that Leikam spotted his first fox, and his journey as a gray fox researcher began.
Leikam was photographing Bullock's orioles five years ago when, while following the birds among the trees, he spotted a gray fox sitting on the edge of the path. She let him get closer, and a bit closer, and a bit closer before casually getting up and disappearing into the underbrush. Leikam came back day after day, hoping for another sighting. The next time he saw a gray fox, it wasn't just the one — there were three of them. “I thought to myself, there’s a whole family living here!” From then on, he was hooked.
Now Leikam visits the area almost every day, twice a day, but with more than just the interest of a passing watcher. He monitors the behavior of the various foxes, watches their social lives play out, watches new litters of pups grow up, notes how territories are established and dissolved. In all his watching, Leikam has become one of the most knowledgeable people about urban gray foxes in the Bay Area, and has seen behaviors never before witnessed, or at least not documented, within the gray fox species.
For instance, Leikam is the first to document helper females among gray foxes. This is a common behavior among other canid species such as wolves and coyotes, in which offspring from the previous year’s litter or even new females entering the territory will stay with the alpha male and female and help them raise the new litter of offspring. However it wasn’t known to happen among gray foxes, until now anyway.
Bill Leikam and Greg Kerekez walk down one of the paths where several of their study foxes live. Leikam notes that along this trail is a den that has been in use for at least 24 years. (Photo: Jaymi Heimbuch)
Leikam has teamed up with Greg Kerekez, a wildlife photographer and videographer, as part of UWRP with the goal of expanding not only how much we know about gray foxes and other urban wildlife but also expanding the corridors through which the animals navigate from habitat to habitat.
Monitoring the daily movements of foxes
Leikam watches the foxes each day and takes careful notes in a field journal, but he also relies on trail cameras to capture action when he is gone.
"Once I become familiar with an area, I look for the main corridor that all of the animals use," explains Leikam. "That way I knew their travel frequency and the directions they traveled at certain times of the night. Once I find where they travel, I then look for signs, depending upon the time of year.
"For instance, when the pups are small, maybe a month or two, I look for open spaces near a thicket where the grass is trampled down in a wide circle because that's an indication that pups have been running, chasing, playing in the area."
By careful placing of trail cameras, Leikam has been able to document an incredible range of behavior, from how foxes raise their pups to how they deal with new visitors who are sometimes welcomed and sometimes viewed as intruders. Leikam and Kerekez study the images and video they gather and document the details that help to create a full, clear picture of the ecology and biology of these urban gray foxes.
But trail cameras can't tell us everything we need to know about these small urban canids. The team hopes to get a lot more high-tech, and are working to raise funds to cover specially-made GPS tracking collars to place on adults and young foxes to monitor where they go and when. This combined with DNA analysis would yield a wealth of information about how the foxes use the urban landscape, and that knowledge would lead to informed decisions about how we can better design our urban areas to accommodate wildlife.
Sharing the stories of urban gray foxes
Leikam has thought about going the peer-reviewed publications route. “Studies are important, but that’s not what I care most about,” he says. “I want to introduce the average, ordinary person to the wildlife in their own backyard.”
So he has been a collector of both data and stories.
The statistics, behavior, routines and population shifts inform us about the foxes of Silicon Valley, but the stories connect us to them, make us care about their fate and understand their small soap operas of family life and survival. While Leikam publishes reports on the status of the foxes on the UWRP website, he is also working on a book that tells the real-life stories of these foxes as individuals and their daily successes and struggles.
The researchers are learning new insights into gray fox behavior, including behaviors never before documented. (Photo: Jaymi Heimbuch)
One significant struggle for this population of foxes is that they are somewhat trapped in this marsh, blocked in by the the freeway on one side, the bay on the other, and residential and industrial development closing in the other two sides. This means there is a DNA bottleneck and there seems to be evidence of inbreeding and the health problems that comes with it.
This is the same problem many other urban species face: The inability to safely navigate larger ranges or to disperse means gene pools may grow stagnate with time. The issue has received large-scale attention thanks to the famous mountain lion of Los Angele’s Griffith Park, P-22. The mountain lion is essentially stuck in the park because freeways and city block access to the Santa Monica Mountains. To ease the problem of migration and open up corridors for P-22 and a wide variety of other species, advocates are raising $10 million to build a wildlife overpass across the nearly impassable 101 freeway.
With assistance from the National Wildlife Federation, UWRP is raising funds for a DNA study to see where possible access points are for new foxes to move in and out of the territory, and push for expanding safe areas for wildlife to move in and out.
“That freeway exchange you took to get here,” Kerekez says, referencing a small patch of trees and dry grass in the middle of a chaotic loop of roads coming off the 101 freeway in Palo Alto, “It’s planted just like any other fox habitat, and there’s a den site in there. We get calls from people all the time who see the foxes, including when they are hit by cars.”
If UWRP can reach their fundraising goals, the team also wants to put GPS collars on the foxes they are studying to learn more about their movements and find out the most important locations for creating passable corridors for foxes, something that would also benefit many other wildlife species as well.
Gray foxes sport a coat that lets them blend in easily with their habitat. (Photo: Jaymi Heimbuch)
Beyond directly monitoring the local gray foxes, UWRP wants to become a non-profit educational organization for reasons on a more local and immediate scale as well.
“We need to educate city parks workers, arborists, gardeners and people who manage the landscape about urban wildlife,” Leikam says.
“They wanted to clear this whole area to put in the trail,” he says, waving his arm over a parking lot-sized green space alongside which runs a multi-use pedestrian path. “They didn’t realize there was a whole family of foxes living here.”
Leikam and Kerekez hope to educate companies, workers and residents about the large-scale and often invisible impacts of spraying weed killer, clearing undergrowth, laying out rodenticide on a multitude of urban wildlife species from raccoons and possums to foxes, owls and hawks. The team also wants to educate locals about how to coexist with their wild neighbors, including preventing conflicts.
Here's a great video that talks about the lives of these foxes and also how we can live peacefully as neighbors with them.
Gray foxes hunt for rodents and rabbits on the ground but also keep their eyes peeled for squirrels and birds that they can capture in trees. (Photo: Jaymi Heimbuch)
The gray fox is the only North American canid adapted to climb trees. It helps them both for hunting and for seeking safety. (Photo: Jaymi Heimbuch)
Identifying traits are used to tell individuals apart, including markings, scars and, in the case of this male, a torn left ear. (Photo: Jaymi Heimbuch)
Bill Leikam and Greg Kerekez survey for foxes at sunrise and sunset, which is when the species is most active. (Photo: Jaymi Heimbuch)