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Posts tagged “Martes pennanti

Fishers Leaving Sign

If you see five-toed tracks, and they don’t belong to a bear, opossum, skunk or beaver, chances are they belong to a member of the weasel family.  Size and habitat help to narrow down which mustelid they belong to.  Although our recent snow produced just a dusting, it was enough to confirm the presence of at least one fisher in nearby woods. Logs appear to be irresistible to these large weasels and are one of the first places to check for their tracks once snow falls.  Even when a log isn’t providing them with a way of keeping their feet dry, fishers often choose it over traversing the forest floor.

Fishers have been actively trapped since the 1700’s and because trapping was largely unregulated, fishers were extirpated in much of the Northeast in the 1930’s.  Restrictions on trapping, the regrowth of forests and the re-introduction of fishers in locations where porcupines were thriving all contributed to the comeback of the fisher. Today they populate most of New England.

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Classic Fisher Sign


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.

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Fishers Climbing Trees

12-19-16-fisher-tracks-up-tree-049a2363If 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.

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Fishers Crossing Logs

11-25-16-fisher-tracks-049a1848The 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.

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Identifying Animals By Their Scat

10-14-16-fisher-scat-20161012_5024Anyone 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.)

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Fisher Raids Wood Duck Nest Box

4-19-16 fisher & wood duck box by Alfred Balch 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)

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Scent Posts

2-17-16 scent posts 026Scent 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.

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Fishers Scent Marking With Scat

1-13-16 fisher bed & scat 002Many 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.

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Fishers Eating Fruit & Marking Territory

11-20-15 fisher scat 134When 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).

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Fisher Hunting Strategy

2-20-13 fisher hunting technique IMG_2988I 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.

Fisher Scat

1-23-13 fisher scat2 IMG_0098Typical 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.

Fisher Landing Imprint

fisher landing IMG_0793Although 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.

Fisher Bed

1-10-13 fisher bed2 IMG_0428Some of the most common tracks in the woods of central Vermont are those of fishers. These members of the weasel family, although known for their agility in trees, travel extensively on the ground. Fishers have been known to cover 28 miles in two days in search of food. They may be active day or night, and especially at dawn and dusk. If you persevere long enough while tracking one, you will be rewarded by some kind of sign in addition to tracks, be it a trampled conifer sapling, or a stump or a log where a fisher has marked its territory by depositing urine, scat or both. Occasionally you will come upon a bed, often right next to the base of a tree, where the fisher has stopped to rest. More often than not, their typical dark scat can be found in these locations.

Fisher and Mink Tracks

1219-12 fisher and mink tracks IMG_2238As 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 often 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. 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. Although not pictured here, both of these carnivores engage in snow sliding, much like their cousin, the river otter, and the resulting grooves are occasionally found when the snow is a bit deeper than it is now.

Fisher Scat

Contrary to their name, fishers seldom eat fish.  While they prey on a wide range of animals and even plants, their preference is for small mammals (80% of their diet), snowshoe hares and porcupines.  Because fishers are well equipped to kill porcupines, and because there is little competition for them, porcupines are an important prey of fishers –up to 35% of fisher diet samples contain the remains of porcupines, as this photograph of fisher scat attests to.  There is no mistaking the bumpy porcupine foot pads (and quills)!

Fisher Tracking

If you ever think you work hard for the food you eat, try tracking a fisher!  I would estimate that I followed a fisher’s tracks for at least three miles today and other than stopping to mark its territory once, and investigate a log or two, there was not a sign of its finding a thing to eat.  Fishers travel widely in search of prey — one was recorded travelling 56 miles in three days.  The fisher I followed traveled through prime snowshoe hare (their most common prey item) habitat, as well as areas where porcupines have been known to den.  A fisher’s food requirements are about one snowshoe hare per week, a squirrel or two per week, or 2 – 22 mice per day.  A porcupine will feed a fisher for a month or so. (Note snowshoe hare tracks on bottom left of photograph, and fisher tracks running diagonally across the image, where the fisher left its mark.)