linda spielman

A Closer Look at Deer Tracks

A deer track–so familiar that we may pass it by without paying much attention. But a closer look at a deer track can reveal some unexpected insights. In the photo above the two main toes (called clouts or claws) show as paired depressions separated by a ridge. In each clout the broader rear edges are rounded and the narrower forward ends are bluntly pointed, so the direction of travel is to the right. When the toes are placed close together the way they are in this photo, the overall shape is vaguely heart-shaped.

Here’s another shot of deer tracks, in this case a left front (at the lower left) and a left hind (at the upper right). Front prints tend to be slightly wider and more rounded than rear prints, but the differences between front and rear are not nearly as pronounced as they are in most other mammals.

Now look at the first photo again: it’s actually a rear print superimposed almost exactly on top of a front (which trackers call a direct register). The clue to the double impact lies in the right toe impression: along the leading part of the outer margin there’s a slight crack and a sloping edge. The outer edge of the left clout is more like a vertical cliff. The left outer edge of the rear foot came down even with the left edge of the front, but the right outer edge landed a little inside.

It helps to have a track pattern when wrestling with such matters. The deer in the photo below was doing an ordinary walk (also called the diagonal walk, for reasons connected with the footfall sequence), and it left the zig-zag track pattern typical of the gait. Each “print” is actually made by two feet, first the front and then the rear on the same side.

The next photo shows the double impact more clearly. In each impression you can see part of a front track with a rear on top and slightly behind (know in tracking circles as an indirect register). I call this the ordinary walk because it’s one of the most common gaits of both wild and domestic animals (and because the term is less abstruse than ‘diagonal walk’), but it’s only one of many variations on the walk. The patterns associated with the various kinds of walks vary, but if you can recognize the zig-zag arrangement of the ordinary walk you’re well on your way to understanding these and other gaits.

But how does that pattern come about? Gaits can be hard to understand, especially if you haven’t spent much time watching animals move. Fortunately there are lots of helpful videos available to make up for this lack. Here’s one that shows the ordinary walk really well: https://www.bing.com/videos/search?q=animal+tracking+gaits&view=detail&mid=11CC299AF70EC963C01211CC299AF70EC963C012&FORM=VIRE.

You should go past the galloping dog and the trotting horse and focus on the third sequence, a horse walking in slow motion. You’ll see each hind foot landing in the place just vacated by the front foot on the same side. If you’re curious about the variations I mentioned there are a few later in the video. For example the first cat sequence is an overstep walk, in which the hind foot passes the front foot track and lands just ahead of it.

When a deer is moving faster or more erratically its tracks can look very different. In the next photo of a left rear print, the ridge separating the clouts widens out toward the front. Note also that the two toe impressions don’t look the same: the left one is relatively level but in the right one the tip area and right edge are deeper. This suggests an energetic turn to the right, and this deer was, in fact, making a playful jump to the right.

The deer tracks in the photo below are even less like our idealized image of deer tracks. This animal was galloping from left to right in soft, moist sand, and its feet sank in so much that both the main toes and the dewclaws made deep impressions. These are both left feet, the front on the left and the rear on the right and the differences in the front and rear dewclaws show nicely. In the front track the dewclaws are closer to the main toes and are angled sideways, while the hind dewclaws are slightly farther behind and point more forward. The energetic movement caused the tips of the toes to sink more deeply than the back parts of the clouts. When the feet came up out of the sand the toe tips dragged and parts of the track walls were broken and scattered, adding to the atypical appearance of the tracks.

If we recognize the kinds of differences I’ve illustrated we can go far beyond basic track identification. Track variations can tell us about the movement and energy of the animal, what it was paying attention to, and maybe even why it was moving the way it was.

Black Bear Days

Black bears habitually cover great distances in search of food, moving from one source of edible treasure to another throughout summer and fall. The animals often find our trails and primitive roads to be convenient travel routes, and the muddy spots that develop in rainy weather are an ideal medium for capturing their tracks. I recently found these tracks on a forest trail used by snowmobiles and ATVs. The direction of travel is to the left; the left rear print is at the lower left and the left front is at the upper right. Bear tracks, especially those of the hind feet, may remind you of barefoot human tracks, but beware–the largest toe lies on the outside of a bear’s foot rather than on the inside.

But even when there’s no mud, you can learn a lot about the daily lives of bears by observing the sign they leave. Bears love fruits of all kinds. The bear that climbed the shadbush trees pictured below probably knew they wouldn’t support its weight. But no matter, it was easier to eat the berries while standing on the ground anyway.

When apples start to ripen, bears climb the trees to get to the sweet fruits in the highest branches. The gouges in the photo below show how the bear’s claws slipped downward before they caught firmly enough for the animal to move farther upward. When feeding on apples or other fruit, bears sometimes break branches and leave them hanging in the tree or on the ground below. Smaller animals like raccoons and gray foxes also climb trees in search of fruit, but their claw marks are narrower and do not show the separation distances of one inch or more that are typical of adult bears.

Insects are a much sought-after source of protein, and bears dig up nests and tear open logs and stumps to get at grubs and larvae. Even whole tree trunks are not too much for a bear’s power. The snag in the photo below was dismembered by a bear. No other animal would have been able to break out the large sections of wood and scatter the fragments in several directions.

It’s not always possible to determine exactly what a bear was after, but in the case of the tree above the evidence–the remains of carpenter ant galleries shown in the photo below–was still present in the large wood sections. Carpenter ants don’t actually eat wood. Instead they use trees as nest sites, and the tunnels and galleries they create in dead wood serve to house their eggs and larvae. Once an ant nest is exposed by a marauding bear the adult ants flee, but the eggs and larvae, and probably a fair amount of wood, are scooped up and consumed en masse.

Bears are also concerned with the movements of other bears, and they keep tabs on each other through various kinds of messages. The bites which decorate the balsam fir shown below were made by a bear standing on its hind legs. To leave such marks a bear sets an upper canine tooth in the bark and draws the lower canine in. This leaves dot-dash patterns like those to the left of the debarked area. The debarked area itself resulted from repeated biting, and the weathered appearance of the exposed wood tells us that the marking had been going on for a number of years when the photo was taken. Such marks may be visible to bears at close range, but more importantly, they hold the scent of the animal which made them, and bears are famous for their keen sense of smell.

This was a large tree, and it must have been a magnet for every passing bear. It stood about twenty feet off of a seldom-used hiking trail, and between the trail and the fir tree there was a narrow passage with distinct step spots. These step spots were created when approaching bears walked toward the tree with an exaggerated swagger, planting each foot deliberately as if they wanted to leave as much evidence of their visit as possible. In the photo below the step spots show as brown areas of bared soil.

Bear sign, and sometimes tracks, can be very abundant, but unless there’s an artificial attractant (such as garbage or handouts) they’re seldom seen. But fortunately for us their strength and resourcefulness can be observed in their tracks and sign. We can even read, albeit on an elementary level, their messages to each other.

Turtles on the Move

One spring a few years ago, as I wandered along the banks of my local stream, I came upon a wood turtle engaged in digging a hole in a gravel bar. She was preparing to lay eggs, and she seemed to be laboring mightily. The spot was very rocky and she wasn’t making much progress.

Finding a turtle in the process of egg laying isn’t that common, and wood turtles themselves are scarce, so this was a very exciting find. But not wanting to create any more difficulty for her, I took a few photos and left. I don’t know whether she succeeded or whether she gave up and looked for an easier location.

Turtles usually find places that are more favorable for digging, like the sandy spot in the photo below. But the eggs in that nest didn’t mature. When young turtles hatch successfully they break out of their shells underground and make their way to the surface without creating much disturbance. The presence of signs of digging and shell fragments on the surface means that the nest was raided and the eggs were eaten, perhaps by a raccoon or a fox.

Although late spring and early summer are the peak times for reproduction, turtles may continue to mate through the summer and even into the fall. Pairing up and egg laying generally involve a lot of travelling, and these wide-bodied and low slung animals leave distinctive trails. The trail below was made by a diamond-back terrapin moving from bottom to top. Each line of impressions was made by the front and hind feet on one side, and the small front tracks alternate with the larger rear tracks. Between the two strings of prints you can see disturbances made by the dragging plastron, and at the very bottom of the frame there’s a small tail mark.

This turtle was walking, but the pattern looks very different from the patterns we see in walking mammals. That’s because the terrapin’s wide body and short legs prevent it from walking the way most mammals do. The turtle was doing an understep walk, the rear foot consistently coming down behind the spot where the front that moved forward just ahead of it was placed. The rear feet touched down about midway between the last front track and the one before that, so the spacing between prints is roughly even.

Here’s another turtle trail, this one made by a painted turtle moving from top to bottom on hard sand. The tracks consist mainly of claw marks, and they lie in sets of two, each set made up of a front followed by a rear. Both front and rear feet have five claws, but the front prints turn inward while rear prints point straight ahead. The gait in this photo is also an understep walk, but the hind tracks are closer to the front tracks than in the preceding example. Although the relative positions of front and rear prints can vary, turtle trails are always variations on the understep walk.

The trail in the photo below was made in dry sand, and the dragging plastron made a wide, smooth mark between the two track lines. Clear prints are not present, and it’s not obvious which way the turtle was going. Two kinds of evidence suggest that the direction of travel was right to left. First, the plastron drags seem to have smooth slopes on their right sides and steep edges on their left sides. And second, the deep holes made by the feet have drag marks pointing to the left.

Turtles are on the move, and their journeys can take them through a variety of habitats. Any area of sand, silt, or mud might show their unique parallel strings of prints and, sometimes, whimsical designs. So when you get a chance, take a detour and check out that patch of sand or muddy shoreline.

Avian Woodworkers

Woodpeckers, like other birds, are raising families at this time of year, and they’re consumed by the need to provide food for their young. Because they find much of their food in the bark and wood of living and dead trees, their feeding sites are usually easy to find. The first clue is often a pile of wood chips scattered around a tree base, like the accumulation at the base of the beech tree shown below.

This tree was alive but just barely–the cankers on the trunk tell us it was infected with beech bark disease. The two excavations visible in the photo, plus many more higher on the trunk, were the sources of the widely scattered debris below.

If your timing is good you may find woodpecker scat among the chips. Here’s a close up–this scat was about 1/4 inch in diameter, contained insect exoskeletons, and had some white uric acid on the mostly black surface. Woodpecker scats are delicate and disintegrate when they’re rained on, so you’re only likely to find them in fresh debris piles.

The cavities below were made in a Norway spruce that was very much alive. New holes are often circular, but as they’re enlarged they become elongated and sometimes connect to form long troughs.

So what exactly are woodpeckers that attack trees eating? Contrary to what you might think, they aren’t eating wood! The photo below shows a close-up view of an excavation. Deep in the recesses of the hole the wood is partially decayed, and you can see that it’s honeycombed with tunnels and chambers. These are the galleries of carpenter ants. They’re actually nests rather than feeding sites–carpenter ants range widely on plant surfaces and on the ground, eating other insects as well as sap and nectar. Both living and dead trees may house carpenter ant colonies, and there could be thousands of ants in one tree, so for a woodpecker it’s well worth the work of excavating holes to get at them.

The photo above also shows cuts and grooves made by the bird’s beak as it chiseled the wood away. These beak gouges are large, up to one half inch wide. The pileated woodpecker, the largest and most powerful of our woodpeckers, was responsible for all of the examples shown above. Only a bird this size could make such large holes, not to mention create such wide beak gouges and leave such large scat.

Although smaller woodpeckers can’t produce the same kinds of massive excavations, they still manage to find plenty of food in the bark and outer wood of trees. Hairy or downy woodpeckers searching for wood-boring grubs removed patches of bark from this hemlock tree.

And the dead maple shown below was also mined for wood inhabiting insects. It’s covered with pockmarks made by smaller beaks, as well as some larger gouges, so it was probably a multi-species feeding site.

Wood, whether living or dead, may host many different types and sizes of insects, including the wood-boring larvae of beetles and moths, insects that nest in wood, predatory arthropods that feed on other wood-inhabiting insects, and creatures that simply find shelter in cracks and crevices. Thanks to this diversity, wood is a rich source of food for many different birds.

Red Squirrel Housekeeping

The snow is gone and leaves have not yet filled in the forest canopy, so it’s a great time to look at red squirrel middens. Conifer seeds make up a large percentage of the red squirrel diet, and the animals spend lots of time eating or collecting conifer cones. To get at the seeds a squirrel holds a cone in both front feet and, starting at the bottom, chews off each scale and eats the exposed seeds, spinning the cone as it works its way toward the tip. This is done with typical red squirrel energy, and the scales seem to fly out at blistering speed. The scales and cone cores accumulate around or below the feeding station, and the resulting piles of debris, called middens, can be quite sizable. The mounds in the photo contain mostly the cores and scales of Norway spruce cones. Middens this large must have accumulated over a number of years, probably during the residence of several different animals.

The hole just below the trunk of the closer tree is an entrance to an underground space where cones were stored. These food caches are often located in the spaces around the roots under the middens, but may also be in rock cavities, log piles, or even human structures. They are generally underground where the high humidity prevents the cones from opening.

Red squirrels depend on stored conifer cones for survival over the winter. In late summer and early fall conifer stands resound with the sound of objects hitting the ground as the animals nip the cones in the tree tops. Once a good supply has fallen, the squirrels descend and carry the cones to their underground storage spaces. It’s this habit of creating concentrated supplies in a limited number of locations, called larder hoarding, that allows the animals to inhabit boreal forests with long, snowy winters. Imagine the effort that would be involved if, like gray squirrels, red squirrels had to dig down through a deep snowpack to retrieve each individual food item. With its food stored in larders a red squirrel merely needs to maintain tunnels leading from the surface to the ground-level entrances.

Middens are usually located at the bases of the trees which provided the cones, indicating that the squirrels bring cones up from storage to perches higher in the tree to feed. In the photo above you can see a Norway spruce with several branches (dead but still strong enough to support a squirrel) which could have served as feeding perches. These branches, or ones nearby, are often marked by the squirrels. One such branch is shown in the photo below. The shot was taken from directly above the branch. You can see some partly eaten spruce cones on the ground below in the upper part of the photo, and the dark tree trunk in the lower right-hand area. The branch itself is liberally marked with the fresh gouges of red squirrel incisors, and there are a few older gouges from previous years. The scent compounds left in the wood would establish the resident squirrel’s ownership of that particular real estate.

Middens tell us how much red squirrels depend on conifers for their winter food supply–and it’s not just Norway spruce. Where pines, hemlocks, firs or other spruce species are more common their cones provide the bulk of the winter diet, and similar middens can be found.

In the mixed forests of central New York, middens tell us about the non-coniferous foods that red squirrels also make use of. In the photo above butternut shells with typical red squirrel entry holes are mixed with the spruce scales and cores. I’ve also found the opened shells of walnuts, acorns, and hickory nuts in red squirrel middens. And occasionally a bone fragment, with telltale incisor gouges, sits atop a midden. Red squirrels, like other small mammals, need to boost their calcium intake by chewing on bones, and a familiar feeding perch makes a fine location for a dose of minerals.

Spring Fever among Woodchucks

If you think you have it bad, just consider the woodchuck. The males emerged from hibernation weeks ago only to find the ground covered with snow. There wasn’t much to eat, and the weather wasn’t very spring-like. But no matter–they were more interested in procreation than food or comfort, and they spent their time searching out burrows occupied by females. Upon finding a receptive female the male entered the den and copulated with her, then moved on in search of another one. With nothing much to eat the roaming males, which may have dropped up to 1/3 of their body weight during hibernation, lost even more body mass. Meanwhile, the female woodchucks remained underground and got a few more weeks of sleep.

This delayed emergence is important because, like the males, female woodchucks have already lost weight during hibernation and losing even more would impair their ability to give birth to healthy young. Their appearance above ground coincides with the onset of new spring growth and their condition improves rapidly.

I found the den pictured below in early March. A few inches of new snow covered about a foot of denser old snow, which made for nice tracking. There weren’t any tracks beyond those shown in the photo, so it looked like the animal came out, took a look around, and then went back into the burrow. The mud-on-snow tracks are remarkably clear–check out the right front print just to the right of center.

Finding such unmarred tracks around burrows becomes less likely as the season advances and the animals make more forays to and from their winter refuges. The photo below, also from early March but taken a few years ago, shows the muddy and partially melted evidence of several trips. In both of these cases the weather was still pretty cold and there was a substantial snowpack, so these were most likely males in the throes of spring (or rather mating) fever.

As winter loosens its grip woodchuck tracks start becoming more widespread in fields and forest edges. In the photo below the direction of travel is from the lower left of the frame to the upper right, and the impressions form a zig-zag pattern. Each angle of the zig-zag is composed of two

tracks, the rear positioned roughly on top of or close to the front track from the same side. These are the characteristics of the indirect register walk, the woodchuck’s most common gait. Starting from the lower left, the sequence in the photo above is right hind on right front, left hind on left front, right front with right hind just ahead, left hind on left front. To the right of the first set of left front and hind there are some gray squirrel tracks heading in the opposite direction.

By the way, woodchucks are also known as groundhogs, but I prefer the name woodchuck, because the word derives from one of its Native American names. Woodchucks weren’t as common in pre-colonial times as they are now, but their populations would have been concentrated around cultivated fields so they would have been familiar to Native Americans. They still thrive in agricultural landscapes, and are sometimes seen as pests. From an ecological point of view they are actually beneficial. Woodchuck excavations help to turn over and aerate soils, and their burrows provide homes for many other animals.

The photo above shows a burrow I found after a very cold night. Rabbit tracks led both in and out, but this hole wasn’t dug by a rabbit. Unlike European rabbits, which construct extensive tunnel systems called warrens, our cottontails don’t dig burrows. They get along just fine without underground housing, unless it’s very cold. When that happens they find shelter, and that shelter is often a woodchuck burrow.

An Encounter with a Fisher

Sightings of wild mammals are generally rare, and when they do occur it’s usually just a quick glimpse of the tail end of the animal as it flees at top speed. So my recent encounter with a fisher was doubly unusual. I was walking downhill on a sloping section of forest road (Hammond Hill Road in Hammond Hill State Forest for those who know the area). That part of the road is straight so I could see pretty far down the hill, and I suddenly realized there was a dark animal moving around on the road far below. I froze, not sure at first what kind of animal it was and hoping it wouldn’t realize I was there. It didn’t–in fact it actually began coming up the hill toward me. As I got a better view of its elongated body, short legs, and long fluffy tail I realized it was a fisher. I watched as it moved in a completely relaxed manner–apparently unaware of my presence–and marveled at its beauty. I was afraid if I made a move to get out my camera the fisher would take off, so I didn’t dare try for a photo. But here’s a good photograph of a fisher obtained from the Vermont Center for Ecostudies (https://vtecostudies.org/blog/walk-with-the-fisher-on-outdoor-radio/).

Photo courtesy of the Vermont Center forEcostudies

The fisher continued to move uphill in my direction at a steady bounding gait, with an occasional pause to look around. When less than 50 feet separated us, it suddenly realized I was there. It stood up on its hind legs, stared at me for a few seconds, and then bounded off into the trees.

Of course I immediately went to look at the tracks. Because the snow was dry and fluffy most of the prints weren’t clearly defined, and the cloudy conditions made things even harder to see–and nearly impossible to photograph. But there was a spot farther down the hill where the snow was firmer and the track details showed up better. A set of four prints from that part of the trail is shown in the photo below (direction of travel from right to left). The pattern

Track sequence, starting from the right: right front, left front, right rear, left rear.

resembles the bound of a cottontail rabbit: the two front tracks are narrowly set behind the rear tracks, and one (the left front) leads the other. The rear tracks are more widely separated and almost even with each other. Typical mustelid structure shows in the prints: the five toes are arranged in a lopsided crescent and the middle pads form a smaller crescent behind the toes.

That was only one of several different gait patterns I saw as I backtracked along the fisher’s trail. In true mustelid fashion the animal had been very flexible in the way it placed its feet. Rather than showing the rather poor photos from that day I’ll illustrate two of the variations I saw with shots that I took on other days (the direction of travel again is from right to left). As in the opening shot the four tracks in the photo below are well separated, but the rear prints are staggered rather than even with each other, and one is positioned slightly behind the leading front print.

Track sequence, starting from the right: right front, right rear, left front, left rear.

In the next shot the left rear foot came down on top of the left front, leaving a pattern that looks at first like there are only three tracks. But in the heel area of the middle impression there’s an inner ridge and a wider area of disturbance to its left, showing that two feet did actually land there.

Track sequence, starting from the right: right front, left rear on top of left front, right rear.

In addition to those two there were other variations–changes in the leading front or rear foot and slightly different placements of the second and third feet to hit the ground–but to my eyes the fisher’s bounding movement appeared to be uniform and unvarying. Except for momentary pauses it moved steadily uphill with the gently arching leaps that are so typically mustelid. One difference did stand out, and that was a variation in the leap lengths: the four-print patterns that matched the one shown in the first photo were separated by slightly longer distances than the patterns shown in the second and third photos. The fisher apparently wanted to move faster, and I suspect that the more even placement of the rear feet in the first photo delivered more power and enabled longer leaps. But there were many variations in the patterns that didn’t involve any changes in leap length, so there must be other factors that cause a fisher to vary the way it places its feet. I can only imagine the subtle interactions that go on between the animal and its surroundings. I hope that with further study of fisher trails, and maybe even some additional encounters with fishers, I’ll be able to understand more of the puzzle.

The Allure of Scent Marking

Deep in the coldest months of winter, when you’d think every animal is single-mindedly focused on survival, some predators are being distracted by an equally compelling urge–mating. Even as the snow flies, time spent hunting decreases and behaviors connected with reproduction become more predominant. For the tracker one of the best signs of this change is an increase in scent marking. I followed a red fox trail recently, and she was detouring to urinate on raised features like this stump every 500 feet or

so. I say she because the arrangement of tracks and the placement of the urine could only have been done by a female fox. In the photo the small spots in the left half of the stump are urine (you can ignore the dark chunk of bark near the center). The fox came in from the lower left, paused on the upper side of the stump to pee, and proceeded towards the upper right. The more deeply impressed track marked SF was made by the supporting rear foot (the left) while the right rear was raised. During mating season red fox urine has a strong, slightly skunky–but not unpleasant–odor that is obvious even to us smell-challenged humans. So as I followed the trail the air was perfumed with fox musk.

My dog Banjo (dogs are great teachers for wild canine behaviors) demonstrates the technique in the photo below, supporting her weight on her right rear foot plus the two front feet and positioning her left rear leg up and forward. You can actually see the urine squirting downward under her rear end.

Male canines also raise a rear leg when they urinate, but the leg is held out and back, and the urine goes out to the side rather than downward. I don’t currently have a male dog so I can’t show you that, but I’m sure you can imagine the posture. A male coyote, traveling from left to right,

made the scent mark above, supporting its weight on the right rear foot (the track at the lower center) and shooting the urine sideways onto the upper part of the stump. Coyote urine has a mild odor and isn’t nearly as detectable by humans as fox urine is.

Bobcats also feel the mating urge in the winter, and again, those who have house cats, especially males, may have observed the technique. A male bobcat left its signature on the log in the photo below, coming in from the top of the frame, depositing its message, and leaving at the lower left.

It first gave the log a good sniff (revealed by the front print facing the log), then turned so its rear was facing the wood and sprayed urine backwards. Here’s the photo again with the tracks marked.

S denotes where the bobcat placed a front foot as it sniffed the log. RH, LH, RF and LF show the four feet in a squared posture as the cat faced away from the log and urinated backwards. Bobcat urine, like house cat urine, has a strong odor of ammonia, so if you had been there to sniff the side of the log you would have detected the cat-box odor. Female bobcats also scent mark, mostly downward from a squatting position.

Scent marking by wild canids and felids continues through pair formation, den preparation, and birthing. Soon after that hunting begins to regain its importance as the pressure to provide food for the growing young increases. But the timing of reproduction isn’t accidental. The earlier onset of predator reproduction means that their greatest need for food coincides with the greatest abundance of prey animals, which mostly mated in early spring and multiply during spring and summer.

The Ups and Downs of Snowshoe Hares

Snowshoe hares are having a banner year. In early December I spent some time in the western Adirondacks, and it seemed like there were snowshoe hare trails everywhere. A bounding hare-like its cousin the cottontail rabbit-typically leaves sets of four prints in Y shaped arrangements. The two larger rear prints are usually even with each other and widely spaced while the smaller front prints are behind the rear, staggered, and placed along the center line of the trail.

In the photo at the right (direction of travel from right to left) the hind tracks are the larger and somewhat triangular prints on the left side. The right front print is near the center of the photo and the left front print is behind it toward the right edge of the frame.

The hare that made the tracks above didn’t sink very far into the snow, so it’s easy to see all four prints. But when temperatures stay low and the snow keeps falling there may be a foot or more of light, fluffy stuff on top that doesn’t offer much support. That’s the way it was during my recent Adirondack visit. Even the snowshoe hares were sinking deeply at every leap, and their landing patterns didn’t look the same.

In the photo at the left a bounding hare traveled from bottom to top, leaving a triangular hole each time it landed. At each landing the front feet plunged into the snow at the narrow lower part of the triangle. The more widely held hind feet–each foot spread out laterally for maximum support–landed just past the front feet to form the wide upper part of the triangle. The width at the widest part of these craters can approach twelve inches.

Snowshoe hares, like cottontails, tend to use the same travel routes repeatedly. This creates trails that offer firmer footing and easier movement, like the one shown at the left. I’ve read that these trails help the hares escape from predators, but I’m not sure about that. Maybe the predators can move more easily as well.

Snowshoe hare populations are known to go through cycles of abundance and scarcity. These cycles are especially pronounced in the Boreal forests of Canada, where population numbers of the Canada lynx are closely tied to the abundance of hares. The Adirondacks host a greater variety of both predators and prey–although there are no lynx–and population fluctuations don’t reach the same extremes for either prey or predators. But when hares are more abundant than usual, as they seem to be in the western Adirondacks this winter, young fishers, coyotes, and bobcats–the main predators of snowshoe hares in this region–are more likely to make it through their first winter. I hope to visit the same locations over the next few months, and I’ll be paying special attention to the tracks and signs of all the animals in the web of relationships that includes the snowshoe hare.

Lessons from Flying Squirrels

The weather has been unusually cold and snowy for early November, and there have been days when conditions were perfect for seeing detail in the tracks of small animals–an icy base with about half an inch of new, soft snow on top. On one of those days I went to a location where I had seen flying squirrel trails in past years, and I found some beautifully detailed prints. In the photo on the right (direction of travel to the right), the right rear track is at the bottom of the frame, and the right front is just above it. The other two prints are at the top, the left rear just behind the left front. The toes and middle pads show up nicely in both front and rear tracks. The heels of the rear prints made impressions, and the paired heel pads of the right front track can also be seen.

Now compare the shot above with these chipmunk tracks, photographed on the same day and arranged almost identically except that the left front track is just below the left rear. There’s a similar amount of detail, with toes and middle pads clearly visible in both front and rear feet and the paired heel pads showing in both front feet. I had hoped that if I found really detailed tracks I would see features that would separate chipmunks and southern flying squirrels, but to my eyes there are no appreciable differences between the tracks in the two photos. The dimensions are similar as well: both sets of prints have a trail width (the distance from the right edge of the right rear print to the left edge of the left rear print) of 2 inches, and the length of the front track is 9/16 inch for the flying squirrel and 5/8 inch for the chipmunk, not significantly different. So how did I know that the tracks in the first photo were made by a southern flying squirrel, while those in the second belonged to a chipmunk?

The answer came from the differing trail patterns. Southern flying squirrels have flaps of skin (patagia) that connect the front and rear legs all the way out to the ankles, so they move differently from chipmunks (and also from tree squirrels, for that matter). The front tracks of a bounding southern flying squirrel are set almost as wide as the rear, and they are usually in front of, or occasionally between, the rear tracks. Because of the skin flaps, flying squirrels are not as fleet-footed on the ground as other small rodents, so their leaps are shorter. Compare the southern flying squirrel bounding trail in the photo above (traveling from bottom to top) with the next photo of a trail made by a chipmunk (traveling from top to bottom). In its normal traveling bound the chipmunk consistently places its rear feet ahead of its front, and its leaps can be much longer than those of the flying squirrel. Of course chipmunks do sometimes make short leaps, and they do sometimes place their front feet between (as in the second photo of the blog) or ahead of the rear. That kind of pattern in a chipmunk trail is an indication of a break in the rhythm, while it falls withing the normal bounding pattern for a southern flying squirrel. (By the way, neither of the bounding photos came from the day I took the close-up shots, but they illustrate the trail patterns I saw that day.)

More snow changes everything. All bounding animals switch to what I call a double-register bound when their feet sink deeply into the snow. The trail pattern consists of sets of two impressions more or less side-by-side, created when the rear feet come down in the holes just made by the front feet. For an animal the size of a flying squirrel even a few inches of soft snow can be enough to change its gait pattern from its normal bound to a double-register bound like the one in the photo at the right (direction of travel from lower right to upper left). The relative positions of front and hind prints no longer apply, but trail width can still be measured, and this trail had a trail width of 2 1/8 inches, squarely in the range for the southern flying squirrel. A chipmunk trail would have had a similar trail width, but the trail pictured above was made during a long stretch of cold weather. Chipmunks wait out winter’s coldest periods in a state of torpor in their underground refuges, while flying squirrels come out regularly even in frigid temperatures.