|fwg is a long-term project of the ottawa field-naturalists' club|
Red foxes at the FWG
by Christine Hanrahan
The red fox (Vulpes vulpes) has been called the cat-like canine, an apt description for this graceful animal with its many feline characteristics.
Red foxes have been around the Central Experimental Farm (CEF) for many decades. Den sites are found in various locations, including some old ones at the FWG. The red fox that we see at the FWG is considered the same species as that found in Europe, Asia and parts of Africa. It is also found in Australia, where it was introduced about a hundred years ago by British immigrants, presumably so they could continue their passion for fox-hunting. At one time, the North American red fox was thought to have been a separate species from that found elsewhere.
The fox is the size of a small dog, weighing from 3.6 to 6.8 kg and measuring approximately 1-1.2 m in length including tail (Banfield 1974, Forsyth 1985). The very light, slender skeletal structure of this animal has evolved to allow speed and agility of movement by decreasing body weight without sacrificing muscle or size.
The name "red fox" is apt, for their coat is a deep, rich, glossy rufous, except for the chest, abdomen and tip of the tail, which are white. The ears are black, as are the lower legs giving the impression the fox is wearing dark socks. The fur is beautifully thick and dense, and the tail is a magnificent, bushy, plume. Colour variations exist, including a melanistic or black phase. Foxes showing a black coat with white-tipped guard hairs are called "silver foxes." Another variant is called the "cross-fox," named for the unusual dark "cross" over its shoulders. I've seen only the typical red fox pelage around the FWG and the Farm.
The sight of a fox in an urban setting still surprises many. No doubt because, although long associated with human habitation, they are so adept at being invisible. Their range extends across much of North America where they live in a variety of habitats. Open or semi-open areas similar to that of the CEF, as well as woodlands and forest openings, are all used. It is thought that red foxes "do best, that is, become most abundant, in country that is varied land that is made up of a patchwork of woodlots, open meadows, dense brushlands, pastures, and small wetlands. The more diverse an area, the more red foxes seem to thrive in it." (Henry 1996).
The FWG contains all of these elements, but of course, in miniature. We could, however, use our site to show what optimum fox habitat looks like!
The fox has many feline qualities, including the remarkable ability to flex and partly retract its claws. It also has much longer whiskers (vibrissae) than most other canines, both on the muzzle and the carpal joints (wrist). Henry (1996) postulates that these whiskers "function as tactile organs. The muzzle vibrissae may help to guide the fox's capture and killing bites, and the carpal vibrissae may assist the fox during stalking."
So similar are they to cats, both in habits and in their very feline way of moving and hunting, that at in the past there was speculation as to whether they were really true members of the dog family. These days we know that they are indeed canids, albeit very catlike ones.
Whether in play, or in earnest pursuit of food, foxes move with an elegance and grace that is pure poetry in motion. It has always amazed me how this animal can spring from a supine position and flee like the wind, "floating over windfallen trees and dense underbrush, as if it were half bird" in the words of J. David Henry (1996).
Although capable of loud, high-pitched barking, foxes are usually silent except in breeding season when they bark to attract a mate or when they warn intruders away from their cubs. Henry (1993) describes the sound as "a slightly drawn-out wail" that will carry for over 1 km. He notes that the bark is given "once or twice per minute in a series of 5 to 15 repetitions."
Foxes are primarily nocturnal, except in winter when they spend much more time hunting during the day. But even then, the best time to see them is very early in the morning, when they are returning from a night's hunting, or after sunset when they are setting out. One early morning encounter remains in my mind as clear today as 30 years ago. It was mid-December and I was snowshoeing across a field east of the city just as day was breaking. Becoming aware of movement ahead I stopped to focus my binoculars. The enchanting sight of three foxes playing met my eyes. Leaping, chasing, jumping, lunging, and stalking each other, there can be no other word to describe what they were doing. It was a remarkable performance, ending only when they got wind of me and melted quietly away. I'm sure they were young of the year, and I decided they must have had a successful hunt and were celebrating. But that of course, is to anthropomorphize them.
The most remarkable thing about foxes, is their ability to remain unseen while living in highly disturbed sites. The CEF is a good example of this. Foxes have been around the farm almost continuously for many decades, and yet they are seen infrequently. They raise their young, dig dens, hunt, and leave signs of their presence throughout the area, but are themselves largely invisible. I have been watching the foxes on the farm for over a decade and even when I know where to look for them, catching a glimpse is more often down to luck not diligence. Many of my sightings have been after dark, when, on moonlit nights, I might catch sight of a fox moving swiftly across the landscape. However, over more than 30 years of fox-watching both around Ottawa and elsewhere, I've also had numerous daytime sightings.
Females hang around their dens before giving birth and can often be seen during the day. I've also come across foxes sleeping against the base of a knoll in daylight hours, or even wandering along back roads. One August afternoon in 2006 while walking around the CEF, I noticed a big flock of crows cawing loudly, clearly in hot pursuit of something, for they were flying relatively low and moving in formation across the cornfields. Sure enough, out of the corn burst a very beleaguered fox. The last I saw, he'd ducked into yet another cornfield still with the crows pointing out his presence to all and sundry.
In 2002, fox observations were at an all time high at FWG. Tracks and scat were found everywhere, and visitors to the garden often told us, with some wonder, that they had seen a fox. Other years prior to 2002-2003 yielded fox sightings, but never so many or as consistently.
During 2004 sightings dropped dramatically, and the one fox I did see was obviously suffering from mange, and clearly unwell. This same animal was last seen at the FWG in winter 2004. A short while later, I found him dead in the New Woods. After that, I saw no foxes anywhere on the farm until January 2006. Foxes are particularly susceptible to mange, which is a serious problem for this species as its impact on local populations can be severe.
The winter of 2006-2007, brought a welcome increase in fox activity, including two foxes at one of their traditional den sites. Occasionally we find evidence of these animals at FWG, but nothing like a few years ago. I suspect that the sheer number of both people and dogs is making the garden less attractive to these cautious animals. But who knows? I hope to be proven wrong!
Foxes prey on a variety of animals, but are themselves preyed on by bigger, stronger species. Once again, however, humans are the greatest threat to foxes. Knowing this, isn't it surprising that they have chosen to live among us? At the FWG, dogs are the worst problem facing foxes and, although I am unaware of any dog having actually killed a fox there, chasing is problem enough. We're next on the list, with our cars speeding down Prince of Wales Drive. I have several times seen road-killed young of the year on this road. One was opposite the entrance to the FWG and presumably had been either coming to, or leaving, the garden. In the wilder areas, coyotes and bobcats are the chief predators on this small canid.
The main food of the red fox is rodents, and at the FWG and the farm this means meadow voles (Microtus pennsylvanicus), mice (Peromyscus sp.), groundhogs (Marmota monax), squirrels (Sciuridae), and cottontail rabbits (Sylvilagus floridanus). However, foxes are omnivores, eating a great variety of food. Banfield (1974) notes that small mammals form the principal prey about 37% of the diet. Birds make up about 20% of the diet, invertebrates about 26%, and plant material 16%. Other items such as snakes, frogs and fish make up the rest. Foxes are opportunistic feeders, taking what is most readily available and easily found. Not surprisingly then, rodents form the bulk of their winter food, while in summer plant material including fruit, nuts, and seeds is added to their diet of small mammals, insects and other foods.
The chief activity of foxes is, naturally, hunting for food. Around the FWG, I've seen them stalking and catching small rodents, particularly in the Old Field and New Woods areas. Very occasionally I've seen them eating apples under the few domestic apple trees (Malus sp.) in the garden.
Foxes have excellent hearing and sense of smell. Fergus (2006) says that they can hear a mouse squeal from up to 45 m away. In winter, their ability to hear animals moving under deep snow, combined with their quick reflexes, gives them an edge at this harsh time of year. Research has shown that their remarkable hearing is better attuned to lower frequency sounds rather than, as in most other animals, high pitches. Henry (1996) says that studies show "these frequencies correspond to the rustling and gnawing sounds that small mammals make."
One morning, I saw a fox feeding on a road-kill groundhog, opposite the FWG entrance. Fearing that the fox might be hit as traffic picked up, I dragged the groundhog off the road. The fox ran when I approached, but later returned and continued feeding. The various rabbits, squirrels, and groundhogs that fall victim to dogs around the site, don't often remain long. Dogs probably scavenge some of them, but it is much more likely that foxes, carrion eaters, are feeding on the remains or caching them for, like many canids, foxes will cache food under snow, leaves or soil.
Henry (1996) says that scavenging, hunting, and caching are "the three prongs of the fox's livelihood (and) combine with its variable diet to make this animal the most adaptable creature." I haven't stumbled across a fox cache at the FWG, but that doesn't mean they are not there, although I'd expect them more around the less-visited areas of the farm.
Territory and home range
Foxes are non-migratory and occupy the same territory year-round, usually marking their boundaries with urine to let other foxes know an area is occupied. Availability of food and suitability of habitat, both determine how many foxes a given site can support. Foxes are generally solitary animals, except during breeding season when a pair-bond is formed. This pair, and later their cubs, occupy a home range that can vary from a few hectares to many thousands of hectares. Banfield (1974) gives an average home range of about 360 ha to 800 ha, depending on food and shelter availability. Compare this to studies done around Oxford, England, where the food-rich environment supports one fox family per 10 ha (Henry 1993). At the other extreme, research in southeastern Iran, has shown that a fox family would inhabit a territory of about 5,000 ha, reflecting the difficulty of finding food in such a harsh desert environment (Henry 1993).
I have not found more than one fox family on the Central Experimental Farm, although I was told some years ago, that there are two family groups. I do know that the area west of Merivale Rd., which once belonged to CEF and is now the site of the Central Park subdivision, held a apir of breeding foxes. When the bulldozers moved in, they disrupted a den site and sent the female fleeing with her young.
It may be that since the foxes use several locations on the farm, observers have assumed two separate families. Or there may occasionally be two family groups. In years when the vole and rabbit populations peak there just might be enough food to support two families, but I wouldn't want to bet on it. The cycles of vole and rabbit don't necessarily coincide, and a peak year for rabbits may be a poor year for voles. One thing is for certain, the FWG alone is not big enough to maintain a single fox, let alone a family. It is the addition of the farm and the Arboretum together with the FWG that provides adequate territory for the farm foxes.
Sometime in January or February, I check out the den sites at the farm to see if any are occupied. This is breeding season for foxes. As winter progresses, the female may be found sleeping or resting on top of the den itself.
Many den sites are located on the side of a mound or rise in the ground, especially those in open areas. I used to think this was for safety (greater visibility over the surrounding area). But Henry (1996) says these locations are probably preferred because "the hillside location and nearby open area, may make for a site where snow melts early, frost leaves the ground quickly and drainage is always good." The den sites I've seen over the years have been in a variety of locations, including on a very obvious knoll, under cedar trees, in thickets, along fencerows with a thin scattering of trees, in belts of conifers, in woodlands, and in agricultural lands. They seem to prefer sandy soil where possible.
Typically foxes will have several dens in close proximity so that if danger, perceived or real arises, they can move their young to a safer site. A den site usually has two entrances, some have three. Foxes may tolerate a lot of disruption, or they may move at the first hint of disturbance. Henry (1996) records unwittingly causing a female to move her young when he "crossed an invisible but important vulpine boundary" in his attempt to get photographs. In 1982, Theresa Ani kowicz (1983) came across a vixen moving her cubs from one den to another near Ramsayville Marsh. She was able to carefully watch, follow and photograph this family over the course of the summer, from the time the cubs were tiny and still without their red pelage, until they grew old enough to be more wary of the world.
Some den sites may be occupied for many years. Several sites on the CEF have been used for at least a decade, probably longer and the animals seem to alternate use every few years.
During the winter, dens will be cleaned out or modified, in preparation for birth. New dens may be dug by the foxes, but often as not they will take over an old groundhog burrow and enlarge it. I know that at least three of the den sites I've found on the CEF have been previously used by groundhogs. I don't know if the dens were still occupied by groundhogs when the foxes took possession. However, Banfield (1974) notes "an unusual interspecific tolerance between the red fox and the woodchuck, with both species occupying the same burrow, has been described." No doubt this is a rare occurrence given that groundhogs are a favoured prey item! Hollow logs are sometimes used as dens. Elbroch (2003) says entrances may be anywhere from 15 to 30.5 cm in diameter. The dens I've measured on the farm, including FWG, have ranged from 15 cm to more than 45 cm in diameter.
At the FWG, there are several very old sites, probably used in the days before the area became so busy and disturbed. One is enclosed in what is now a thicket of trees and shrubs. This particular den had several entrances, one quite large. Another den was on a steep slope, invisible to most people, well protected by trees. Yet another den was under a clump of conifers, but has since almost vanished, filled in by leaves, needles and other debris.
Gestation takes about 51 days (Banfield 1974, Forsyth 1985, Henry 1996). The kits or pups, weigh approximately 100 g when born (Banfield 1974) and are dark gray, charcoal, or dark brown. During the 1970s, in the Dunrobin area, I found a fox den in a hollow log; nearby was a dead kit, probably not more than a couple of weeks old. It was entirely black. According to most sources, the pups are blind and helpless for the first 10 days. However, they develop quickly and in no more than a month are able to leave the den. It is not uncommon to see them playing around the site, always under the watchful eye of mother. By this time, they have attained the orangey-red pelage that we associate with the species. One year I counted five youngsters at a den site on the CEF, but typically I have not seen more than three or four. Banfield (1974) and others give the average litter size as five.
There is nothing quite so adorable as a young fox. A few years ago I came across three of them on the CEF, playing tug-of-war with a green garbage bag. They were making little growling sounds, and every so often one of them pulled loose a piece of the plastic and went flying backwards. I watched them for about 2 minutes before their mother got wind of me and gave a warning bark. The females are naturally very protective, and several other times I've been treated to examples of their vigilance. Once my dog and I were "chased" off by a very determined and very vocal vixen. When we had moved to a safe distance, she sat down and continued watching for some time, as if to say "And don't come back!" A few weeks later, from a distance, I saw a couple of young kits close by this same site. In the fall, I went back and poked around the area. Sure enough, there was a den, now unoccupied, well hidden by shrubs.
Given their hunting skills, ingenuity and adaptability, one would think that foxes, if they can avoid predators, should live a relatively long life in the wild, but this doesn't seem to be the case. Banfield (1974) says that tagging experiments "indicated a longevity of at least three years, but there seems to be a large turnover each year." Forsyth (1985) concurs with this number but adds that they have the potential to live up to 12 years.
At summer's end, the young will disperse to find their own territory. Banfield (1974) notes that studies have shown some males will disperse up to 267 km, although it seems that the average distance is about 69 km. Some will not make it past their first winter, victims perhaps of cars, predators, disease, or starvation, if they have not learned to hunt successfully. Some may return to the farm in the following year and take over their natal den if the adults have left or died in the meantime. But one thing is for sure, if we allow these animals to do so, they will remain at the farm, successive generations raising their young and taking care of business for the farm by controlling the rodent populations. You could say, they are earning their keep.
Winter is a harsh time for all animals. Those who do not hibernate must contend with finding shelter and enough food to survive until spring. Foxes are more adept than many at getting through the winter thanks to their ability to find and catch small rodents. At this time of year, meadow voles and mice, active throughout the winter, form the greater part of their diet. Yet finding enough of this tiny prey to fuel their energy requirements means the fox spends long hours hunting in winter which in turn uses up precious resources.
When a fox detects a rodent beneath the snow (or in the grass, for that matter), it will pounce or lunge (two very distinct and different movements) and either pin the animal down with its paws or grab with its mouth. I've seen them doing this at FWG, along with some very quick frantic digging through the snow to reach their prey.
Foxes also prey on rabbits and squirrels in the winter. To catch these animals they must be fast. I've watched them stalking and chasing squirrels which are remarkably good at eluding capture, at least much of the time. Rabbits rely on stillness to avoid detection, but are no match for the fox with its keen senses. I found an area on the CEF where a well worn and scat-littered rabbit trail ran from a small burrow in the midst of a raspberry thicket to a stand of sumac on which it fed. Not long afterwards, I found only a few scattered rabbit remains (photo at right) along with some fox scat. It looked like the fox had dined well.
Finding warm, secure shelter is also important for animals in winter. Opinion varies as to whether dens are used at this time of year. Foxes can be found curled up under shrubs, usually against a knoll, brushy tail covering their nose, sometimes covered in snow. Henry (1993) says that they will use dens throughout the year, to escape inclement weather including heavy rains and summer storms, as well as for protection from frigid winter weather. I've noticed foxes investigating dens around the farm during the winter, some of which show signs of active use. One winter, several volunteers at the FWG made it their mission to see if they could find out whether foxes were using a well protected den in the garden. A fox was seen in the vicinity many times, and fresh tracks on the snow led to and away from the den. This led to speculation that the animal was using the den at least some of the time. From what I have seen, I would say that foxes do use dens in winter.
During the winter of 2002-2003, we often saw a fox during the day at FWG, along the trails, near the pond, in the BYG catching grey squirrels or other prey, or napping under sumacs on the south side of the ravine. For several weeks this individual curled up in the same ravine spot, directly opposite the Interpretive Centre and visible from several windows. Occasionally a dog would scent it and give chase. Perhaps this happened once too often, because eventually the fox vanished from that location, presumably finding somewhere quieter and more protected.
The red fox is a remarkable and beautiful animal, the sight of which is always enchanting. Their adaptability to new situations and to a diversity of habitats, as well as their legendary ingenuity, has made them true survivors. If you have observed foxes around the FWG or the farm, I'd love to hear from you at firstname.lastname@example.org.