When your quest is to find out as much as you can about the identity, activity, diet and territory of your four-footed neighbors, it is logical to make the most of all your senses. Tracks can be seen, scrapings and bite marks on a tree can be felt and yes, one’s sense of smell can enhance any tracking expedition. Just as the tracks and scat of different species of animals have distinctive characteristics, so does the urine of different animals. Scent marking, including urination, is a behaviour used by animals to identify their territory, and therefore a highly visible sign in winter.
At this time of year, foxes are breeding, and without even putting your nose near where a fox has marked his territory with urine, you can detect its skunk-like odor as you pass by. If you’re so inclined (and I realize many readers may not be) you can heighten your sensory experience as well as your identification prowess by sampling the smell of other animals’ liquid waste. White-tailed deer urine has a pungent, piney smell, quite pleasing to this naturalist’s olfactory receptors. You can detect a porcupine den from a considerable distance by the pungent, very distinctive but hard to describe odor of its urine (which spills out onto and coats the bark of a tree den, thereby advertising the porcupine’s presence). Coyote urine smells very much like a domestic dog’s, and members of the weasel family often have musky-smelling urine, though a recently-sniffed fisher marking had very little scent.
Needless to say, it’s a lot easier to discover and sample urine when there’s snow on the ground and it is more evident. Virginia opossums, snowshoe hares, red and gray squirrels, eastern coyotes, red and gray foxes, raccoons, fishers, mink and striped skunks are all in or entering their breeding seasons, when scent marking is more frequent. Snow is currently on the ground, at least in northern New England. It’s prime time for olfactory activity, if you’re game. (Photo: stump marked by a red fox)
As members of the weasel family (Mustelidae), Fishers and Mink have five toes on both front and back feet. Often all five digits do not register, but in prime tracking snow, you can sometimes see them. Typically, mink tracks are found near a body of water, and fisher tracks are found under a canopy, not in the open. Where you have both water and trees, it’s possible to see signs of both animals.
In general, the larger the animal, the larger its tracks. Mink weigh one to three pounds; fishers four to eighteen pounds. In this photograph, the mink tracks (smaller, in the middle) are heading towards the top of the photograph, and the fisher tracks (top most and bottom most) are heading towards the bottom of the photograph. They were both traveling on a frozen woodland stream.
Although capable of climbing trees, Fishers spend most of their time on the ground under dense woodland canopy. In the winter Fishers constantly leave sign while traveling two to three miles a day in search of squirrels, shrews, mice, voles, porcupines, hares and grouse, among other things, to eat. Beds at the base of trees, small saplings bitten, rubbed and rolled on, scat and urine marking – all are quite commonly encountered when following Fisher tracks. The Fisher sign I find quite elusive and therefore very rewarding to come upon is the imprint they make when they land in the snow after jumping down from a tree they’ve climbed. (Photo: landing imprint)
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Last week’s post on a fisher’s spruce sapling scent post showed evidence of rubbing (broken, bare branches) and scat. Since then, the fisher has returned (scent posts are used repeatedly) and because there’s fresh snow, you can now see where it rolled. I thought this might (?) be of interest to some readers.
Fishers are one of the most rewarding mammals to track as they leave so many signs. One of the most common ones, other than their tracks, is their scent posts. This is where a fisher rubs itself, anointing the substrate with its scent as it marks its territory. Young saplings often serve this purpose. The fisher rubs and rolls on a young tree, often a conifer, usually breaking a few branches.
If you see a scraggly-looking sapling in the woods, and there are fisher tracks nearby, examine the sapling closely for fisher hairs that often get caught on the branches when a fisher rubs against them. More often than not, the fisher will also mark the tree with a bit of scat or some urine. Fishers are very adept at controlling the amount of feces they leave, often excreting very small portions as markers throughout their travels.
If you look at the tree in the center of the photograph, you may be able to detect paired tracks in the snow along the length of its trunk. As luck would have it, a fisher chose to ascend the one tree with snow still clinging to its trunk. Fishers are members of the weasel family and are well known for their ability to climb trees. They do so in order to reach den sites as well as to catch prey. Fishers’ arboreal adaptations include semi-retractable claws and ankle joints that rotate so that they can descend trees head-first. Smaller females appear to be more adept in the trees than the larger males.
The first snow that sticks on the ground is cause for celebration, if only because it allows you to know so much more about what goes on in the woods and fields that surround you than you would know if it never snowed. At this point the snow isn’t deep enough to distinguish tracks very well in the leaf litter, but thanks to the fisher’s propensity for crossing logs (which are relatively smooth, an excellent substrate for tracks, and retain scents well), one resident’s presence was announced loud and clear recently.
Fisher have large, wide feet with five toes on each foot and semi-retractable claws. This makes them well adapted for walking on snow, climbing trees and grasping and killing prey. (They are also capable of rotating their hind feet nearly 180 degrees, which allows for a headfirst descent from trees.) Their track is very distinctive, and can be quite common in forested areas of the Northeast.
Usually, if given the option, fishers will choose walking on a log over walking on the forest floor. Why would they have developed this preference? There often is no water where this occurs, so it’s not done in an effort to avoid wet feet. My best guess as to the purpose of this behavior is scent-marking. Fishers have been observed sliding along logs on their bellies, as they rub the scent of their anal glands along the top of the log. The fisher scent-marks with cheek, abdominal, neck, flank, and plantar (feet) glands, in addition to anal glands. A fisher leaves its scent with every step of its hind feet, and if rotting logs are superior scent-absorbers, it may be why fishers choose them over the forest floor.
Anyone who has tried to discover what wildlife resides in their woods knows that signs of animals are much more likely to be seen than the animals themselves. One of these signs is an animal’s scat. There are different factors regarding scat that help to reveal the identity of the animal that left it. One is where you find it. Different animals deposit their scat in different locations. For instance, foxes typically do so along and at the intersection of trails, Fishers often use stumps or other elevated surfaces.
Another helpful hint is the shape of the scat. Many mammal species have distinctively-shaped droppings, but they can vary depending on the animal’s diet. If you open any book containing scat descriptions, and turn to the page on Fishers, you will undoubtedly come across descriptive words such as “twisted”, “black”, “tapered”, and “pointed ends.” Indeed, if the Fisher has consumed prey, its scat is usually as described. But if the Fisher has been eating fruit, which they often do in the late summer and fall, its scat is tubular and quite smooth, with little twisting. While scat can be an excellent clue to the identity of an animal, interpreting it can be tricky! (Pictured is tubular Fisher scat filled with the seeds and skins of grapes behind old, rained-on Fisher scat filled with fur and bones.)
Lying at the base of a large Eastern Hemlock I recently found two piles of bleached bones. One pile consisted of mostly vertebrae; the other pile had numerous tibias, humeri and ribs. All were the appropriate size and shape to have come from several Eastern Chipmunk skeletons – at least four or five. How did they end up in two distinct piles?
The lack of any fur indicated that regardless of how these bones came to be here, they were deposited quite a while ago. The lack of any partial skulls or jaw bones and the large number of bones in each pile led me to believe that these were not the remains of two pellets that had been regurgitated by resident Barred Owls. No wild owl pellet I’ve ever dissected, including the large pellets cast by Snowy and Great Gray Owls, has contained even half this many bones, and most contained at least part of a jaw bone.
If not pellets, then scat? How likely is it that a predator could catch and consume multiple chipmunks rapidly enough so that they would end up in the same pile of scat? One feasible explanation could be that a fox, coyote or fisher preyed on young, inexperienced chipmunks, but the bones were adult-size bones.
Perhaps these two piles are the remains of a predator’s cache – perhaps a bobcat?
The possibilities are endless as to how this chipmunk graveyard came to be. However, none of the theories proposed here can explain the dissimilarity between the types of bones in each pile. If any naturally curious readers have insight into this phenomenon, your thoughts are welcome!
Fishers are rarely seen, as they tend to travel in wooded areas and not expose themselves in open areas. However, this fisher was so intent on getting a meal that he threw caution to the wind. Fishers are generalist, opportunistic hunters and scavengers, consuming a wide variety of animals and plants. Basically, if it can catch it, a fisher will eat it – amphibians, reptiles, invertebrates, birds and bird eggs, and mammals (snowshoe hares are at the top of the list, but rabbits, squirrels, small rodents, shrews, and porcupines are common prey).
Between its keen sense of smell, and its acrobatic abilities (due to the flexibility of its hind feet, which can be turned 180°), a fisher is able to take advantage of prey and access food wherever it may be – in the tallest tree, or, in this case, a wood duck nest box.
Noted New Hampshire naturalist/tracker/videographer, Alfred Balch, succeeded in documenting the pictured fisher swimming out to an active wood duck nest box, climbing inside and exiting with a wood duck egg gently held in its mouth. It was observed doing this more than once. Considering that wood duck clutches consist of anywhere from 6 to 16 eggs, this fisher’s stomach was probably full by the end of the day. The wood duck is the only duck in North America that regularly produces two broods in one season, so hopefully the second clutch will escape the fate of the first. (Photos by Alfred Balch)
Scent posts can serve as territorial markers as well as a means of conveying hierarchy, breeding status, gender, fitness, etc. When you think of a scent post, where an animal deposits its scent either by rubbing, urinating or defecating, one often thinks of it as being used by one animal to communicate with other individuals of the same species. However, for whatever the reason, a rock, stump or the junction of two trails can prove irresistibly appealing to more than one species. Each chooses to leave messages for other members of its respective species at the same location. In this case, two predators, a Fisher (left) and an Eastern Coyote (right), left their scat at the base of a rotting stump. The tracks of both of these animals were evident throughout the area. In sharing the same scent post, were they vying for the same territory, advertising for a mate (both are at the peak of their mating season), or simply making their presence known? Unfortunately, the human nose isn’t equipped to answer this question.
American Martens (formerly Pine Martens) are making a comeback in northern New England. On New Hampshire’s Threatened Species List, and on Vermont’s Endangered Species List, American Martens are rebounding from the effects of habitat loss and trapping in the early 1900’s, but are still considered rare. This medium-sized member of the weasel family is slightly larger than a Mink and smaller than a Fisher, and often has a light orange bib, or throat/chest patch. Lighter fur usually is found on their head and along the edges of their ears. In addition to a pair of scent glands, which all weasels have, American Martens have a glandular area on their lower abdomen that exudes a musky-smelling, oily secretion used for scent marking.
American Martens spend a lot of time in trees. Their semi-retractable claws help them climb and hang onto branches. In addition, their hind limbs can be rotated at the ankle (like Gray Squirrels) to allow them to descend a tree very quickly, and their long, bushy tail helps them balance.
Because they store very little fat, martens must hunt every day. In the winter they are active for about four hours a day (14 hours/day in the summer), and during this time consume an average of three voles or the equivalent amount of chipmunks, birds or other small rodents. A sighting of an American Marten is a highly-prized experience. (Thanks to Laurie Stokes, whose photo of a Pine Marten was taken in the White Mountains of New Hampshire.)
Many animals communicate by scent marking in order to stake out territory. This is done through specialized glands on various parts of their bodies as well as with scat and urine. In addition to defining territory, scent marking may also communicate additional information such as the sex, reproductive status or dominance status of the territory-holder. Fishers are a prime example of a scent marking predator. In addition to scent marking with glands on their feet, fishers rub, urinate and deposit scat often near or on raised surfaces (stumps, rocks, saplings), where their scent is likely to be widely dispersed. Frequently scat will also be found near a fisher’s resting spot.
When marking with scat, fishers are somewhat unusual in that it appears that they can control the size of the scat they leave. While field guides say fisher scat is between two and seven inches in length and roughly ¾” in diameter, this is not always the case. (Neither is it always dark and twisted – some fruit, such as rotting apple in the pictured scat, will cause it to be lighter colored.) One wonders what determines the size of the scat that a fisher leaves. Does it plan on marking a great deal in the coming hours, and so parcels it out in bits and pieces so as not to run out? Or is a large amount not always necessary if it has back-up scent from its feet and body? The pictured scat (to the right of the depression a fisher left while resting at the base of a tree) is less than an inch long, and about 1/3” wide — roughly the size of a white ash seed. Chances are that after spending enough time in one place to melt crusty snow the fisher was capable of leaving far more feces, but it chose not to.
Ruffed grouse typically have a short life span; few live to be three years old. By mid-August about 60 percent of the grouse hatched that year are lost to predators, weather extremes, disease, accidents (such as flying into windows) and hunters. Less than half of the surviving young survive through the winter to have a chance to breed in the spring, and less than half of those that survive long enough to breed make it to a second mating season. The hazards for a ruffed grouse are many, with predation at the top of the list.
Birds of prey, especially the goshawk and great horned owl, take many grouse, but terrestrial hunters such as foxes, coyotes, bobcats and fishers also take advantage of this plentiful food source. Along with hares, porcupines, squirrels, mice and voles, grouse are one of the fisher’s preferred foods. A fisher managed to capture a ruffed grouse in the pictured scene, leaving only tracks and a few tell-tale feathers to tell the story.
When one thinks of fishers, meat-eating predators come to mind. While it is true that the fisher is a generalist, opportunistic hunter and scavenger, and feeds on any prey it can catch and kill (snowshoe hares, rabbits, squirrels and other small rodents, birds, bird eggs, smaller weasels, shrews, porcupines, raccoons, amphibians, reptiles, carrion and a very occasional cat or chicken), it also consumes fruit and nuts, especially when prey is scarce.
Given the amount of apples that are available this fall, even if prey isn’t hard to find, it is not too surprising to see fisher scat composed solely of apples at the base of this scent marking post (confirmed by fine fisher hairs at the very tip of the stump as well as scat).
For seekers of animal signs, tracking a fisher is a most rewarding endeavor. Fishers are constantly marking their territory – rolling on and breaking limbs of conifer saplings as well as urinating and defecating on or near saplings or on prominent, elevated stumps or rocks.
More than other members of the weasel family, Fishers can control the amount of scat they deposit, so that there can be a minuscule amount, or a full-size scat (2” – 7” long). Perhaps because of their predilection for marking with their scat frequently, they often use this medium sparingly.
The color of Fisher scat is usually dark brown or black, but once in a great while one happens upon fisher scat that is bright orange – a sure sign that the fisher has lived up to its aquatic name and has dined on crayfish in the recent past. Fishers primarily prey on snowshoe hares, porcupines, ground-nesting birds and smaller rodents. However, they do frequent streams that remain open in the winter, where they hunt for crayfish and, very rarely, fish.
Rabbits and hares comprise much of a Bobcat’s diet, but when prey is scarce or hard to capture, adult male or sometimes large adult female Bobcats will attack bedded, weak or injured adult White-tailed Deer. Bobcats often cache prey (such as a deer) that is too large to eat in one feeding, returning to feed on it for an extended period of time. They scrape up leaves, bark, twigs, soil. snow – whatever is available – and cover their prey. When feeding on a deer, Bobcats bite away the hair to avoid eating it, and this discarded hair is frequently mixed with the debris that the cat drags over the kill to cover it (see main photo – taken the day after the deer was cached), or is left windblown around the carcass. A characteristic sign of Bobcat feeding is the amount of hair strewn around the carcass and the lack of broken long bones (Bobcats don’t have the strength to break them with their teeth).
Typically a Bobcat rests near its cache to protect it, but it doesn’t take long for other animals to detect and take advantage of an easy meal. Within three days of this deer being cached, Coyotes and Common Ravens had discovered it, and both they and the Bobcat had eaten enough of it to expose the deer’s rib cage (see insert).
Other predators that occasionally cache and cover their kills include Mountain Lions, Black Bears and Fishers. Large caches found in the winter in the Northeast are likely to belong to a Bobcat or Fisher (Fishers typically cache and feed on deer that they find as carrion).
(Cache discovered by Lynn & Otto Wurzburg, who observed the Bobcat leaving after caching the deer; photograph by Lynn Wurzburg)
This winter has brought us several storms that have ended in rain and were followed by plummeting temperatures. Just a few inches down into the powdery snow on top of the ground there is a ¼”-thick crust, and if you dig down several more inches, there is a second layer of ice, roughly 1/8”-thick. When a thick, icy layer of crust forms, it can have a dramatic effect on the lives of wildlife both above and below it.
Some animals are relatively unaffected by the presence of a crust but many predators and prey are significantly helped or hindered by it. Ruffed grouse cannot seek overnight shelter from the bitter cold and/or predators by diving into a foot of soft snow and creating a snow cave (see photo). On the other hand, small rodents have a distinct advantage — mice and voles have several layers of ice between themselves and hungry coyotes, foxes and owls. Snowshoe hares lose the advantage they usually have on deep, soft snow — “snowshoes” that keep them on top of the snow when the bobcat or fisher chasing them has to flounder through it. Turkeys don’t have the strength to dig down through one thick crust, much less two or more, in order to reach hidden acorns. If a deer is being chased, its pointed hooves will break through the crust, slowing the deer down, whereas the crust may well support a lighter predator, allowing it to outrun the deer. Red squirrels have to work much harder to reach their cached winter cones and to create tunnels.
What is a mere inconvenience to us humans literally is costing as well as saving the lives of wildlife this winter.
The drama that goes on in our woodlands is never-ending, and winter provides us with a window into life and death scenarios. One of the most sought-after prey animals in northern New England is the snowshoe hare. Bobcats, lynxes, coyotes, foxes and fishers are some of the mammalian predators of this lagomorph. In this particular case, however, the predator had wings (determined by wing imprints in the snow and lack of tracks). While great horned owls do prey on hares, there was a tell-tale sign that it was a hawk, not an owl, which produced this pile of fur and bones. If you look to the upper left of the photograph, and to the upper right, you will see lengthy curved lines of bird droppings, or sprays, that were left by the predator as it plucked its prey. Because it was ejected forcibly, and didn’t just drop down on the snow where the bird was situated, the scat leads one to the conclusion that it was a hawk, not an owl, which deposited it. A woodland accipiter capable of capturing a snowshoe hare after an extensive chase, which this was, is the northern goshawk. (Thanks to Nicole Cormen for photo op.)
You can spend days following the tracks of a fisher – this tireless member of the weasel family travels up to ten miles a day during the winter, foraging for food and stopping to bed down periodically. One of the more common signs of fisher, other than tracks, is their resting spots. Fishers are active day and night, but even they have to stop now and then to rest, often at the base of a tree. More often than not they defecate before departing. If you look closely you’ll see the fisher’s scat – guide books often state that the scat of fishers is dark and twisted. While this is sometimes so, their scat can also be somewhat mustard-color and not be at all twisted, as in this photograph.
I have never heard of this particular fisher hunting technique, nor have I seen or read about it before, but there’s no denying that a fisher made these marks in the snow and that they tell the story of how it captured a mouse or vole. It’s likely that the fisher could hear or smell that the rodent tunnel in the subnivean layer was occupied. It looks as though the fisher methodically scraped snow towards the center of the circle, going completely around the tree in an attempt to trap and/or expose the mouse or vole within the circle. It succeeded in opening up the rodent tunnel (the hole is in the dead center of the photograph), and if the tiny droplets of blood on the snow near the hole are any indication, was successful in capturing its prey.
Typical fisher scat is anywhere from ¼” to ¾” in diameter, very dark and often quite twisted. It’s not unusual to find just a small amount of scat deposited, as fishers can control the amount of scat they use to mark territory. This scat is a bit atypical, in that it is segmented and not twisted, and there is an ample amount. A close look reveals the dark, stiff hairs and quills of a porcupine, likely the fisher’s most recent meal. Look for fisher scat on raised surfaces such as stumps or at the base of old trees, where fishers occasionally make latrines.
Although fishers are agile climbers, they catch most of their prey and do the vast majority of their traveling on the ground. Occasionally, often in coniferous forests or if threatened, they will climb a tree. When they decide to come down, they jump and land on all four feet. If there is snow on the ground, the fisher leaves an impression, the clarity of which is determined by the depth and relative dryness of the snow. In the wet snow we’ve had recently, a fisher’s four feet left clear tracks when it landed on the ground, and you can even see a slight depression where its head touched the snow. Sometimes the tail is also evident. In this photograph, you can tell the direction in which the fisher intended to head without even looking for further tracks, just from the angle of its body.