snow tracking – Linda J. Spielman

Grouse Scat

I’m fascinated with ruffed grouse scat. We can learn a lot about any wild creature from its scat, but there’s something especially interesting about grouse poop. Grouse are herbivores, and about 80% of their diet is buds, leaves, flowers, fruit, and seeds. The other 20% is insects, spiders, snails, and small vertebrates. Their primary reliance on plant foods is reflected in the fibrous nature of their scat, which is made up of curved, cylindrical pellets like those in the photo below. The scats have blunt ends and are 3/4 to 1 1/4 inches long and 3/16 to 1/4 inches in diameter. They are brown to tan and usually have a splotch of white uric acid at one end.

Sometimes the white ornamentation is missing, as in the photo below.

Grouse scats are often found in heaps or groups, as shown in the photos above and below. These collections may mark the location of an overnight roost, or they may just be at a random spot where the bird paused to empty its colon.

When there’s a winter snowpack it’s easier to tell if a pile of scat marks an overnight roost. If temperatures are low and there’s plenty of soft snow on the ground, grouse spend the night buried in a snow bed. To do this a bird flies low and plunges headfirst into the snow, adjusting its position until it is surrounded and covered with snow. Before it leaves its snow cave in the morning the grouse may relieve itself, leaving a pile of scats like the one shown in the next photo.

Occasionally grouse scats are scattered rather than grouped. In the next photo you see a grouse drumming log, a site used by male grouse for mating displays. The birds strut back and forth and beat their wings to produce deep booming sounds. These displays draw in females, and if the hens are impressed they may allow the male to mate with them. A large log with scats dispersed erratically over its surface, like the one in the photo, is almost certainly a drumming log. The colors of the grouse pellets in the photo vary from dark gray to bright brown, indicating that the log has been used several different times for drumming displays.

Ruffed grouse produce a second type of scat, called cecal scat. In the photo below you see a bowl-shaped depression, a roost site, with a collection of normal scats in its center. A little below and to the left of the roost there are several darker, larger scats with pointed ends. These cecal scats are produced from two structures called ceca that are attached to the large intestine. The stuttering tracks to the left of the cecal scat make me wonder what the grouse was experiencing as the scat was being deposited.

There is some debate about the function–or functions–of the ceca, but they are believed to be involved with the fermentation of cellulose. The evidence is pretty strong: the winter diet of the ruffed grouse is high in cellulose, and along with the increase in high-cellulose foods the grouse’s ceca also become enlarged and cecal scats become more common. Research has also been shown that the microorganisms found in the ceca at these times are capable of digesting cellulose. Ruffed grouse are not the only birds that produce two kinds of scat. Turkeys, ptarmigan, and other grouse species also routinely eliminate cecal scat. I’ve found ruffed grouse cecal scat in winter and early spring but never in summer or fall.

As I’ve worked on this post I’ve realized that there’s much more I want to learn about grouse scat. Are there visible changes in grouse scat as the diet transitions from woody plant buds to leaves, flowers, and fruit of spring and summer? Are seeds ever recognizable in grouse scat? How does the scat appear when large quantities of invertebrates or small vertebrates are eaten? Are there differences between winter and summer cecal scat? And how about other large, herbivorous birds, such as turkeys and geese? I’ll just have to pay much closer attention to the scats of all of these birds in the future.

Good Luck for a Fisher

I was out with a group of fellow trackers last weekend, and we came upon an unusual trail. There was a groove several inches wide running through the snow, and what seemed at first to be disorganized tracks next to the groove. We saw spots of blood in the groove. It looked like the trail of a predator carrying a prey item, and we spread out to investigate. I backtracked, wondering if I’d be able to find how it originated, and it didn’t take long before I came to the scene shown in the photo below.

A wider view, shown in the next photo, shows the rabbit tracks coming in from the upper right at an easy pace, making a turn to the right, and ending near the base of the shrub. The predator’s tracks (hidden behind the branches in the upper part of the photo) showed leaps of varying length moving in a linear path toward the shrub. Just before it passed beneath the leaning branches the animal made a few short leaps, then turned right to make the kill. The rabbit tracks didn’t show any evasion behavior, and the predator didn’t seem to be in a hurry as it approached the shrub. These details suggest that it was a chance encounter rather than a pursuit or ambush. The rabbit either didn’t realize the predator was near until it was too late, or froze when it detected danger.

The trail leading away from the kill site was easy to follow: a deep groove with tracks along one side.

Most of the tracks were indistinct, but there were a few that were clear enough to reveal that the predator was a fisher. There’s a fairly good one in the center of the next photo. I suspect that this was a female fisher, for two reasons. The tracks shown in the preceding photo are in a loping pattern, but their arrangement suggests a labored gait rather than the effortless lope we usually see in fishers. And the groove is quite deep, indicating that the body of the rabbit was not held very high off the snow. A male fisher is large enough to carry a rabbit easily, but a smaller female would have more trouble.

The trail proceeded through the woods in a generally straight direction. Spots of blood appeared every once in a while.

There were several places where the fisher put the rabbit down and either rested or repositioned it.

Finally I saw the feeding site at the base of a pole-sized sapling, shown in the next photo.

A closer shot shows plenty of fur, some entrails, and lots of blood. One hind foot lay at a distance from the main deposit of remains, but other than that I saw no bones or body parts.

I wondered why there were there no bones or body parts left at the feeding site. The condition of the tracks at the kill site and along the trail suggested that the fisher killed the rabbit early in the morning, so there would have been time for scavengers to work over the remains before we arrived in the afternoon. There were lots of coyote and raven tracks around the remains, so they were probably responsible for removing much of what the fisher didn’t consume. I also wondered why the predator carried its prize for so long before stopping to eat it. Something made the fisher feel unsafe, and it may have been the presence of coyotes in the area. We’ll never know for sure. But what’s a tracking outing without an unanswered question?

We don’t often find stories of predator-prey encounters recorded so completely. The fisher was in the right place at the right time, and so were we.

Furry Feet

It’s been awhile since I’ve put out a new post, due to some medical issues I’ve been having. But things have improved, so I’m happy to be back in action.

Going barefoot, or more accurately, bare-toed, is quite popular among wild mammals. The tops and sides of the feet are typically furred, but most mammals in our region touch the ground with bare skin. This applies to both toe pads and middle pads, and sometimes the heel area as well. In the photo of red squirrel bounding tracks below (direction of travel toward the top) the hind tracks are set more widely above the front tracks. The clean borders and smoothly compacted interiors of the toe and middle pads–and the heel pads in the front prints–are unmistakable evidence of bare skin.

But there are a few inhabitants of our region that buck the trend. The feet of rabbits and hares, for example, are thickly furred, and this fur has a blurring effect on the impressions of the toes and pads. In the photo below you see the tracks of a cottontail rabbit bounding toward the left. The toes are visible, but they lack the clear outlines and smoothly compacted interiors seen in the squirrel tracks shown above.

The fisher is another animal with thickly furred feet. The tracks in the photo below were made by a fisher loping from lower left to upper right, and the toes and middle pads are almost completely muffled by the fur.

In the preceding photo the snow was cold and dry, but if the snow is wetter the toes may be more recognizable. The next photo shows tracks made by a loping fisher traveling from lower right to upper left. In the warmer and more easily compacted snow the toes made visible impressions, but the blurring effect of the fur can still be seen in the middle pad and heel areas.

River otters share many features with fishers but differ in having unfurred toes, middle pads, and heel areas. In the next photo there’s a collection of otter tracks (as well as a few dog tracks). The otter loping pattern in the middle and lower part of the photo (direction of travel from lower right to upper left) is the important part, but it’s a little confusing so bear with me and I’ll try to sort things out. Starting at the lower right the sequence of the otter loping tracks is right front, left front, right rear, left rear. There are a few more otter tracks in the upper area of the photo, and in between the two otter front prints there are two dog tracks, a front with a rear just to its left, oriented to the right. The otter prints in the loping array, especially the left hind print at the far left, show the clearly outlined toe and middle pads and the smooth heel areas characteristic of bare skin. And incidentally, the rear dog print also has cleanly outlined toe impressions made by toes of bare skin.

We have two species of foxes, one with furred feet and the other without. The unfurred feet belong to the gray fox. In the cluster of gray fox prints in the next photo the rightmost and leftmost tracks were made by front feet, and the clearer of the two tracks in the middle was made by a rear foot. The distinct margins bordering the toes of both front and hind prints, and the middle pad of the front track on the right, are evidence of skin covered pads.

Red foxes have thick fur covering almost all of the undersides of the feet, and the blurring effect can be seen in the next photo (rear print on the left, front print on the right, and direction of travel toward the left). But here things get a little complicated. I said the feet were “almost” completely covered because there are two places that don’t grow fur. In the middle pad of the red fox’s front foot there’s a curved ridge, sometimes called the bar, which is unfurred–it can be seen in the front track at the lower right in the photo. There is also a small, hairless oval near the tip of each toe on both the front and the hind feet. In the photo these bare regions show as dark spots in the tips of the toe impressions.

Although tracks in snow usually reveal the presence of fur, mud is better for rendering the fine details. In the next photo you see the front print of a red fox oriented to the right. The fur pressed into the mud shows as thin striations in the toe and middle pads. The unfurred parts of the foot, the bar in the middle pad and the small hairless ovals in the toes, interrupt the striated texture left by the hair.

Felines are characterized by bare toes and middle pads, so their tracks have the cleanly outlined pads of other animals with unfurred feet. But bobcats have separate, interesting feature connected with fur. The fur covering the tops and sides of the feet is very thick, especially in winter. When snow conditions are right this fur pushes into the snow around the outside of the track, creating what’s called a hair halo. In the photo below of a bobcat’s right front print (oriented toward the right) the hair halo shows as a sloping bevel outside the toes.

Hair halos aren’t generally seen in house cats–or canines for that matter. In the next photo you see a coyote front print bordered by abrupt walls rather than a sloping bevel. The inclines at the front and back of the track are entry and exit disturbances, and the grains of snow scattered over the track are due to a light snowfall which must have ended just after the track was made. And as a side note, only bare toes could have made the very distinct and cleanly outlined toe impressions you see in the photo.

Do furred feet help in survival? Probably, since thicker fur over the whole body develops as winter approaches. Are furred feet essential to survival? Probably not, since only some mammals have this trait. For the tracker, it’s enough to recognize furred feet as an interesting characteristic and to appreciate the effect fur has on tracks of some animals.

Getting a Good Night’s (or Day’s) Sleep

All animals need to sleep, but the evidence of sleeping creatures can be hard to find. There is, however, one animal whose beds are often more visible–deer. And there are details in deer beds that can make for some interesting insights.

Deer beds are oblong or oval and measure between 25 and 45 inches in length. Mature bucks make beds covering the upper part of the range, while does and yearlings generally fall toward the lower end. But beware: there may be outliers in both sexes. The oval shaped form shown in the photo below was made when the body of a sleeping deer melted the light dusting of snow and compressed the leaves.

But the shape in the photo above isn’t a perfect oval. About half of the outline is evenly curved (the part in the upper left quadrant of the photo), and the remaining part (in the lower and right-hand area of the photo) is more irregular. This is because deer curl up when they sleep–the back is curved, the legs are drawn together, and the head is tucked back along the body. This creates two kinds of outlines: a smooth curve where the back is and a more broken outline where the legs and head lie. The sleeping fawn shown in the photo below (positioned similarly to the way the deer would have been in the photo above) is a perfect example.

Even without snow to emphasize the outline, the position of the animal can often be determined. In the photo below the dried and compressed leaves that were underneath the deer’s body reveal the oval shape. The orientation is similar to the bed and the fawn in the photos above, and the back of the deer formed the smooth curve in the upper left quadrant. In the upper right part of the photo the leaves are drier but not pressed down–perhaps the deer shifted its head occasionally as it slept. The uneven boundary at the lower right was made by the tucked legs.

Both of the beds in the preceding photos were on forested slopes with little understory growth. This, combined with their location near feeding areas, suggests that they were night beds, convenient for episodes of feeding but with good escape routes should danger threaten. Day beds are more likely to be in areas with thick cover. and may or may not be near feeding areas. The animals usually bed down for most of the daylight hours, and day beds may or may not be near feeding areas.

If an animal shifts its position while it rests or a bed is used more than once, the bed may not be oval. Two beds can be seen in the tall grass shown in the next photo. The compressed area in the foreground was used repeatedly and possibly even by more than one deer. It’s about twice the size of a normal bed, and its shape is anything but oval. The same is true for the bed in the background (in the upper right of the photo). These were probably day beds, because they weren’t close to areas normally used by people and the tall, weedy growth provided excellent cover.

Of course, the best recording medium for deer beds is snow. In the photo below the deer’s orientation was the same as in the bed shown above, and the curve of the back is evident in the upper left quadrant. The outline isn’t complete because it was disturbed by deer and dog tracks where the upper back and neck would have been. The interior of the bed is mostly a concave hollow–this is where the animal’s back and side rested on the snow. The deer’s hocks and lower legs formed a trough in the lower center of the photo, and its knees dug into the snow toward the upper right. If you were at the scene and were able to feel the concave area, you would find that the surface was hard and icy. This is because the snow is first melted and compressed by the warmth and weight of the deer’s body, and then refrozen after the animal stands up and cold air hits the bed. As the animal rises it often steps in the still soft interior of the bed, leaving what’s called a stand-up track. There’s a nice one just to the left of the hock impression.

I’ll end this post with an interesting story. I live near the edge of a small village, and deer often walk through my side yard, heading toward the village center in the evening to feed and back out toward the surrounding fields and woodlots in the morning to bed down for the day. One morning a few months ago, I watched a deer walk through my side yard in the opposite direction from normal, toward the interior of the village. I was intrigued, so later that day I followed the deer’s route toward a hedgerow that separates my back yard from my neighbor’s. I was startled when a deer jumped up out of the weedy growth and galloped away. You can see the hedgerow in the next photo.

The growth was quite dense, and it took some effort to push through it toward the place where the deer seemed to have come from. As I got closer I could see the bed through the vegetation (shown in the next photo).

I struggled closer yet and there it was–a definite deer bed.

I took the next photo standing right next to it.

The compressed area was a little bigger than a normal bed and more oblong than oval, which told me that the deer had used the bed several times. Until I discovered it, the spot was a perfect day bed, well shielded and undetected by the humans in the back yards which surrounded it.

Although I’m keeping my distance, I don’t think that particular deer has been back to my hedgerow. But maybe a different animal has discovered the spot. The deer still walk through my side yard in their dusk and dawn travels, and as my scent fades from the area it may again attract a deer seeking a good day’s sleep.

The Secret Lives of Voles

Unless you own a cat with an inclination toward hunting, you’ve probably never seen a vole. These little rodents prefer to lead their lives out of sight, spending their time hidden in thick grass, tunneling in forest leaf litter and humus, or sheltering beneath the snowpack. They are sought out by many predators, but their secretive habits and prolific rates of reproduction allow them to thrive.

There are a number of vole species, and they all have chunky bodies, short legs, and stubby ears, like the meadow vole pictured in the photo above. As the name suggests, grassy fields and meadows are the domain of meadow voles. They’re also known as meadow mice or field mice, although wild mice (white-footed and deer mice) differ from voles in their lifestyles and dietary habits. Another common vole species is the woodland vole (also called the pine vole), which prefers forests but also frequents orchards. Voles are not to be confused with moles, which are insectivores, not rodents.

When conditions are right, voles do reveal their presence to us. In winter this can happen when the snow forms into icy crusts which the small creatures can’t penetrate. In the next photo the hard crust was covered by a shallow layer of new snow, and voles (probably woodland), could only bulldoze their way through the softer top layer. Why the meandering pattern of grooves? The animals may have been searching for food, or for cavities leading to underground spaces. Woodland voles are more fossorial than meadow voles and often dig tunnels in the upper layers of forest soils.

When winter snows accumulate, voles find safety and plenty to eat under the snowpack. Meadow voles range throughout snow covered fields, creating runs that they use repeatedly as they search for food. The evidence of their travels shows up after the snow melts as grooves in the flattened grass thatch like those in the next photo.

The diet of meadow voles is diverse but usually includes grasses. Cut sections of grass like the ones in the next photo are often found after the snow disappears.

Another kind of evidence to be found in newly exposed vole tunnels and feeding areas is vole scat, which consists of tubular pellets like those in the central part of the next photo.

The construction of subnivean runs involves the removal of dirt and plant material from active runways, and once winter is past these appear as windrows of debris. The ones in the photo below were made by a meadow vole. Woodland voles leave similar piles of dirt and humus on the forest floor.

When the snow is deep voles are able to access an additional food source, the inner bark of woody plants. Large chews made by voles can be seen on the white pine in the next photo–this would have happened when the animals were safely hidden by deep snow. The thin layer of living cambium cells is the only nutritious part, and fragments of the inedible outer bark sometimes accumulate below the chews.

Tiny tooth marks, like the ones on the buckthorn stem in the next photo, can sometimes be seen.

In the warmer months vole sign is harder to find, but if you wander slowly through grassy fields and meadows you may make some interesting discoveries, especially when vole populations are high. Small openings like the one in the photo below are the first clue to the presence of the shy creatures.

Vole runs are usually completely hidden by the covering of grass and thatch, but if you spread the grasses backward from an opening, you’ll expose the corridors used by the voles.

If you’re very alert as you walk through a field, you may find a meadow vole nest. I found the one shown below in mid-May, so it was only partially hidden by new grass growth. Later in the season they’re much harder to find.

In the next photo you see another unoccupied nest that I opened to show the finely divided fibrous lining. Winter nests like this one are well insulated against the cold. Exits to the tunnel network can be seen at the upper left and the lower right.

Vole populations go through cycles of abundance and scarcity, and when numbers are high, changes in behavior may bring the animals into the open. During a population boom you may–if you stand very quietly–catch a glimpse of a vole as it pops out of a tunnel. But whether or not you ever have that experience, there’s always evidence of the presence of these animals to be found if you know what to look for.

When Animals Break the Rules

Bobcats walk in direct register. Deer walk in indirect register. Red foxes have a bar in the middle pad of the front foot but not in the rear foot. Fishers move at a lope or bound. Cats have four toes. These and other statements are the received wisdom of the tracking literature. But are they always true? As we’ll see in the following paragraphs, there are exceptions to even these seeming inviolable maxims.

Let’s start with walking deer. They do indeed place their feet in indirect register most of the time. The photo below shows tracks made by a deer walking in indirect register toward the upper right. At the lower left you see a left rear print partly superimposed on the left front print. Roughly in the center of the photo there’s a right front track with a right rear track partly on top but a little behind. At the upper right the left rear track sits a little behind and slightly to the inside of the left front track. The zig-zag pattern is the signature of the walk, and each set of impressions is made up of the front and rear prints from the same side. It’s the partial superimposition of the two prints that makes it an indirect register walk.

Direct registration occurs when the rear print is perfectly superimposed on the front print. As the next photo (the trail of a white-tail deer walking from right to left) shows, this does occur, especially in younger deer.

As this close-up (from a different trail from the one shown above) shows, direct registration makes it hard to tell if the track was made by two feet or just one. Among all the deer trails you see, there are bound to be a few that show direct registration.

Bobcats are said to walk in direct register, but again this is not an absolute. The bobcat trail in the photo below (direction of travel from left to right) is in very obvious indirect register. The zig-zag pattern indicates the walk (and as a side note, you can see how much narrower it is than the zig-zag of the walking deer). In each set of two prints the hind print falls partially but not perfectly on the front print.

In case you have some doubts, a close-up from a different part of the same trail will convince you that this is indeed a bobcat trail.

Was the bobcat distracted? Or tired? We’ll never know. Later in the same trail the animal switched to an overstep walk, a gait that’s often seen in bobcats, so its overall behavior didn’t throw up any red flags.

The next photo shows a direct register trail made by a bobcat walking toward the upper left. In each impression you see what appears to be a single track, but is actually two tracks, the rear print superimposed on the front print. And here’s another interesting aside: The concave hollows around the tracks are not connected to registration, but were instead made by the thick fur covering and surrounding the bobcat’s feet. They’re known as hair halos.

Staying with felines for the moment let’s look at toes, which are supposed to be four in number (counting those which normally touch down) in both wild felines and domestic cats. In the next photo you see some tracks which are clearly feline, but don’t fit the four-toed paradigm. My friend Ben Altman has two house cats, both of which have feet with more than the standard four toes. This is called polydactyly and it’s caused by genetic mutations. It’s not uncommon in domestic cats but is rare in wild felines.

We’re told that fishers prefer to move at a lope or a bound but this, too, is not always the case. In the next photo you see a fisher trail going from lower left to upper right and a red fox trail moving from bottom to top. The fox is travelling at a lope, a gait similar to the habitual gait of a fisher. But what’s the fisher doing? Definitely not the typical lope or bound. Because the front tracks of the fisher are larger than the hind tracks we can work out what the gait is. At the very lower left in the fisher trail there’s a right rear print, and the sequence of the next eight tracks (up until the pattern changes at the upper right), is: right front, left front, right rear, left rear, right front, left front, right rear, left rear. This extended pattern shows that the fisher was speeding along at a flat-out gallop. Fishers don’t often do this, but they obviously can. Something alarming must have pushed the animal into unusual speed.

One of the absolute statements we often hear has to do with red fox tracks. The going wisdom is that there’s a bar or crescent shaped depression in the middle pad of the front track, but not in the rear track. A ridge of horny skin that protrudes through the hairy covering of the pad is the source of the bar, and it’s supposed to be absent from the middle pad of the hind foot. Here’s what we’re accustomed to observing–notice the bar in the front middle pad (on the left) and the absence of the bar in the rear middle pad (on the right).

But on rare occasions we see red fox tracks with a bar in the middle pad of both the front and rear prints. Here’s one example. The front track is at the lower right and the rear track is at the upper left.

Just so you don’t think this is a one-off, here’s another example. The front print is in the upper right and the rear print, with a reduced but visible bar, is at the lower left. (The carboard square in the upper left is one inch on a side.)

Raccoon trails are a common find, and the next photo shows the way a raccoon pace-walking trail is supposed to look. What we expect to see is sets of two prints, each set a front from one side and a rear from the other side. In the photo the direction of travel is from lower left to upper right, and the hind prints are larger than the front prints. Starting at the lower left, the first set is left front with right rear, the second is right front with left rear, the third is left front with right rear, and the last is right front with left rear.

The raccoon which made the trail in the next photo (direction of travel lower left to upper right) appears to be in serious violation of the rules of tracking. Instead of alternating front and rear tracks there are two sets with left rear and right front, then two sets with left front and right rear, and again two sets with left rear and right front. Can a raccoon even do that?

The answer is, no, a raccoon can’t do that. But two raccoons, one following close behind the other, can do that. It you focus on every other set of two you’ll see a normal raccoon pace-walk trail. So what appeared to be an impossible situation turns out to be a perfectly normal, albeit unusual, event.

We need to learn what’s most common in animal tracks and trails, but we also need to think out of the box when faced with uncommon track and trail patterns. Whether it’s two animals conspiring to create a confusing trail, or one animal with an unusual track or behavior, nature can always throw up something we’ve never seen before. It may take days, weeks, or even months to understand what we saw, but that’s part of the excitement of tracking. It’s why we keep coming back for more.

Bringing Home Dinner

When we come upon a site where a predator killed a prey animal, we’re able to see in detail the interaction between hunter and hunted. But finding such a site is a rare. It’s more common to find the trail of a successful hunter carrying its prey, and this also makes for fascinating study. To understand such a trail we must pick out the crucial evidence from the other disturbances that occur in animal trails. Let’s start with a fairly straightforward example.

In the photo below you see a trail made by a fisher loping from left to right. There are three typical fisher track groups, each group a place where the fisher landed and then took off. Above each track group you can see a curving gouge in the snow made by something the fisher was carrying. But what exactly was being carried? Could it have been a stick? Not likely, based on the length of the trail involved (it went on for quite a distance) and the consistency of the patterns. There’s also the fact that the marks are curved, suggesting that the item being carried was swinging slightly. (If you visit a place where dogs have been playing with sticks you’ll see how different it looks when a stick is being carried.) The predator would have been gripping the body of its prize, and something that extended to the side would have touched the snow at each landing. The curving marks are actually made up of two parallel lines, and these lines seem too widely separated to be claw marks from a dangling foot. Their size and positioning do seem about right for the tips of wing feathers, suggesting it was a bird. If it was a bird it couldn’t have been large, since it only touched the snow at the low points in the fisher’s bounding gait. A turkey would be much too big, and even a grouse would probably have left more traces in the snow. Perhaps it was something the size of a blue jay or a junco.

A short-tailed weasel bounding from upper left to lower right made the trail in the next photo. The trail consists of paired track impressions, a common pattern for small mustelids. To the left of each set of weasel prints there’s a thin, slightly curved line in the snow. There’s also a shorter and wider mark just ahead of the weasel tracks. The thin lines are the right size for a tail, and the wider depressions could have been a foot. Given the small size of a short-tailed weasel, it’s likely that the predator was carrying something equally small. A white-footed mouse seems unlikely, because its long tail would have made a longer stroke in the snow. My guess is either a meadow vole or a woodland vole.

The next photo shows the tracks of a fisher loping from right to left, and just below the tracks you see a wide groove. Below that groove you can see several lighter lines. These finer marks aren’t completely parallel with the deeper groove, so the deep groove and the fine lines must have come from separate body parts. The wider groove seems too deep and even to be something as light as a feather–was it a tail or perhaps a thickly furred foot? The finer lines could be the marks of dragging claws. This example is less clear than the two preceding ones, but I’m inclined to think the prey item was a mammal, perhaps a rabbit.

Now to some examples of marks that we often find in animal trails that don’t indicate dragging parts of a prey animal. In the next photo you see the trail of a long-tailed weasel bounding from bottom to top. There are grooves behind each landing spot, but they weren’t made by something being carried; the marks were made by the animal’s tail. Each time the weasel took off for the next bound its body sank into the snow, and the tail left a tapered groove. Tail marks are always connected to body impressions rather than being off to the side of the tracks as they are in the three preceding photos.

Here’s another example of potentially confusing disturbances that are not indicative of something being carried. The next photo shows the trail of a fisher walking from the lower right to the upper left. The fisher dragged the tips of its feet through the snow with each step. Notice that the drag marks are within the trail rather than to the side, and each drag mark extends completely or partially between two tracks.

Drag marks aren’t always as obvious as the ones shown above. In the next photo you see the trail of a coyote walking from top to bottom. In the lowest part of the photo there’s a thin line that was made by a single claw. There are wider gouges above that made by the rounded tips of the feet. But again the grooves lie within the trail width and always connect to tracks.

In the next photo we see what at first glance looks like the trail of some kind of otherworldly creature. It’s actually several coyote trails moving from left to right on a frozen waterway. To sort this out we need to focus in on the trail of each individual animal. The central part of the sequence draws our eye first: There’s an wavy drag mark that seems connected with the series of tracks in the center. If we look at just those tracks we see that they were made by a walking coyote. The drag mark seems to touch the prints, but toward the right it swings to the side and misses the tracks. This tells us that it’s not a foot drag but something that’s being carried. Above the central area there’s a similar string of tracks, and if we concentrate on those we see that they were made by another walking coyote. A third track sequence which lies below was made by yet another walking coyote. The outer trails are close to, but not on top of, the central trail, so there must have been two animals following close behind the one with the food item.

This scenario is supported by the next photo, which was taken in a place where the coyotes slowed down to go through a culvert. The tracks are closer together and the drag mark is more irregular. The drag mark touches one coyote print but misses the others, so it wasn’t made by the coyote’s feet. It’s definitely evidence of something being carried.

As to what was being carried, we can say it was a medium-sized object with a blunt projecting part and enough weight to make a deep groove in the snow. Claws would be thinner, an animal’s nose would be wider, an ear would be softer, and a tail would be fluffier and lighter. That would seem to eliminate all the medium-sized, winter-active animals in our region. But there’s another possibility: the detached body part of a deer with a protruding bone. The area where I found these tracks is a popular spot for hunters, and in mid-December, when I took the photos, coyotes would still have been scavenging on deer carcasses.

I’ll never know for sure, but a deer part is a reasonable conjecture, and conjecture is often what we’re left with when we attempt to understand the trail of a predators carrying dinner. Even without definite conclusions, the process of sorting out the details can be satisfying in itself.

A Family Resemblance

Rodents are the most common mammals on earth, in both number of individuals and number of species. They are also the most diverse, with lifestyles that range from semiaquatic through fossorial (adapted for digging and living mostly underground), terrestrial, arboreal, and even semi-aerial (gliding flight). But don’t let that mind-boggling profusion intimidate you. In our region many of the most common rodents are members of the squirrel family, a group that is remarkably uniform in physical features. Fortunately for the tracker this uniformity extends to track details and track patterns, and familiarity with the key features will aid in the recognition of any member of the group.

In the photo below you see tracks made by a gray squirrel bounding toward the top of the photo. The five-toed rear tracks lie in the upper part of the image, and the four-toed front tracks can be seen in the lower part. Claw marks show as tiny pricks ahead of the toes of both front and rear tracks. Notice that the toe pads of the three middle toes of each hind print are lined up close together, while the inner and outer toes lie farther back and angle to the sides. Behind the toes you can see a C-shaped grouping of middle pads. The front tracks have only four toes, but again the central two point more forward while the outer and inner ones point to the sides. C-shaped arrays of middle pads sit behind the toes of the front prints, and heel pads (there are two on each foot, but it’s hard to tell in this image) are situated behind the middle pads.

Bounding is the most common gait for most members of the squirrel family, and the resulting pattern is another recognizable trait of the group. In the photo above the two rear prints are almost even with each other and are set wider and well ahead of the front ones, which are also nearly even with each other. This positioning may seem odd, but there’s a logical explanation. At each bound the animal lands on its front feet and draws its rear feet forward so they pass outside of its front legs. As the front feet lift off the rear feet touch down–ahead of the spots the front feet just left–and propel the next leap.

The next photo shows a bounding pattern made by a red squirrel, again travelling from bottom to top. There’s a striking similarity to the first image of the gray squirrel tracks, in both overall arrangement and track details. Because the substrate was softer the rear feet of the red squirrel (in the upper part of the frame) sank in deeper–notice that the whole length of each of the three middle toes registered as a narrow groove. Nevertheless the three toes are closer together and oriented more forward than the outer toes, just as they were in the gray squirrel tracks. In the front tracks of the red squirrel (in the lower part of the photo below) the claws show as grooves rather than pricks, but the overall structure is similar to the front tracks in the preceding shot. If you look at the red squirrel’s right front print (at the lower right in the photo below) you can see clear impressions of the two heel pads.

The chipmunk tracks in the next photo (again bounding toward the top) are consistent with the features we saw in the red and gray squirrel prints. In the right rear print (in the upper right quadrant) you can see that the middle toes are closely grouped and the inner and outer toes are angled to the sides. The left front track (in the lower section a little below and to the left of the right front track) shows the four clawed toes, the C-shaped grouping of middle pads, and the two heel pads.

Mud is great, but winter is also fine for seeing squirrel family connections. In the photo below of red squirrel tracks in snow (bounding toward the top, of course) you see the same characteristic features you saw in the mud tracks. As sometimes happens, the heel area of the right rear foot (at the upper right of the photo) registered as a flattened area behind the middle pads. (If you look back at the first photo of the gray squirrel prints you’ll notice that the heel area of the left rear foot also made a slight impression.) There’s a variation in the arrangement of the front tracks, with the right front well behind but the left front farther forward. This kind of foot placement is often seen in squirrels, but is less common than the more four-square pattern.

Flying squirrels possess gliding membranes (the patagium) which extend between the front and rear legs, and because of this the rear feet can’t pass as far ahead of the front feet as they do in red or gray squirrels. In the next photo you see a bounding pattern made by a southern flying squirrel (oriented toward the top) in which the front prints are situated between rather than behind the rear prints. In northern flying squirrel trails the front prints often lie ahead of the rear ones. Another special flying squirrel trait is the thick covering of fur on the undersides of the feet. Because of this flying squirrel prints rarely show the crisp detail found in the tracks of other members of the squirrel family. But even with these differences, flying squirrel tracks will remind you of the tracks of other squirrels.

In the next image you see a bounding pattern made by a woodchuck. If you didn’t realize that woodchucks belong to the squirrel family, the familiar features of their tracks should make that clear. Woodchucks are more likely to walk than bound, and when a woodchuck does bound it usually places its front feet in a staggered pattern rather than even with each other, as in the photo. Nevertheless, the overall arrangement and the track details are consistent with those of its relatives.

To complete the picture for small rodents in the Northeast we need to add a few creatures that don’t strictly belong in the squirrel family but leave distinctly squirrel-like prints. These include white-footed mice, meadow voles, and their allies. I include mouse and vole allies because each one represents a group of closely related species which are difficult to distinguish from tracks alone.

First, let’s look at tracks of the white-footed mouse, shown below in a bounding pattern heading toward the upper right. In spite of its smaller size, the animal made tracks that are uncannily similar to the tracks in the first three photos. If I didn’t tell you that an individual rear print is just half an inch across you’d be hard pressed to tell these tracks from squirrel tracks.

Vole tracks also show striking similarities to the tracks we’ve already discussed–but with a few important differences. In the next photo you see tracks made by a meadow vole bounding from bottom to top. The track sequence, starting at the bottom, is: right rear, right front, left rear, left front. This staggered arrangement is common in vole trails and differs from the more consistent four-square bounding patterns usually seen in white-footed mice and tree squirrels. Voles can leave more regular bounding patterns, but they often move at something between a bound and a lope and their track patterns tend to be more variable. The toe impressions in vole tracks also tend to be more finger-like than the toes of mice. In spite of these differences the tracks of voles will remind you of mouse and squirrel tracks.

This is all well and good, you may say, but if these creatures are so similar to each other, how can I tell them apart? I’ve mentioned a few variations that can be helpful, but often the most useful trait is size. There’s a neat size progression, and although there’s some overlap between adjacent species it’s usually possible to make an identification with a few measurements combined with other clues. There are two dimensions to consider: track width (more reliable than track length) and bounding trail width (measured perpendicular to the direction of travel across the widest part of a bounding pattern). I’ll focus on the big picture rather than giving an exhaustive account of the numbers–detailed measurements can be found in any good tracking guide. White-footed mice and the smaller voles (woodland voles, for example) are the tiniest of the lot, and meadow voles are slightly larger. Chipmunks come next, and southern flying squirrels are slightly larger than chipmunks. Northern flying squirrels outweigh their southern kin, and red squirrels are larger yet. Gray squirrels beat out red squirrels, and woodchucks complete the series. These differences in body size are reflected in differences in track and trail dimensions, so a few measurements are usually sufficient to clinch an ID. Even when the tracks you’re dealing with are in the overlap zone there are usually other clues that can point toward an identification. And when all else fails, it’s okay to say you just can’t be certain. If you treat each situation as a learning experience, you’ll find yourself stumped less and less often.

Gray Fox Affairs

It’s been a strange winter. In my neck of the woods we had some significant snow early in the season, but no big storms since then. Temperatures have been up and down (more up than down), and with all the melting, the snow we do have has consolidated into a dense, icy layer. Much of the time the conditions have been terrible for tracking, but every once in a while something wonderful has happened: warmth and liquid precipitation have been followed by dropping temperatures and a change from rain to snow. When this happens, snow that falls while the air is still relatively warm becomes bonded to the crust. As the temperature drops and additional snow falls, it forms a soft layer on top. The result is a non-slip and easily navigable surface that is a perfect medium for recording tracks.

A few days ago I encountered just such conditions: an icy base covered by a thin layer of soft snow. I was in an extensive natural area, and both the forest road I was following and the surrounding landscape offered beautiful tracking conditions. Animals of all sorts had been moving easily over the snow, and there were tracks everywhere. I found myself following the trail of a gray fox. The animal went for quite a distance at an easy trot, but then it did something that was quite puzzling.

The photo below shows the fox trail as it goes from upper left to lower right. (You can also see a coyote trail to the right of the fox trail, and a mountain bike trail to the right of that.) As it entered the frame the fox was walking (the first three tracks at the upper left). In the next section (between the last walking step and the edge of the tree shadow) the pattern was very different, and following that the trail looks unlike either of the previous sections. I wanted to know what was going on and why the middle section looked so different.

In a situation like this the first thing to do is identify each track. The zig-zag of the walking section helps us to tell right and left, and the fact that the front foot is larger than the hind foot distinguishes front from rear. The next photo shows a gray fox front print on the left and a gray fox rear print on the right. You can see the difference in overall size and also the difference in the sizes of the middle pads.

The photo below shows just the puzzling middle section, and if you compare photos you’ll see that the front and rear in the photo above are actually the first two tracks in the middle section. It’s pretty clear that the first four prints in the photo below are left front, left rear, right front, right rear. After that it gets harder. The track just above the right rear is smaller than the one to its right, so those two prints must be left hind, left front. Three tracks from the right side come next, and it looks to me like the sequence is right rear, right front, right rear. The final two before the tree shadow are the left front and the left rear, and at the edge of the tree shadow there’s a right front with a right rear partially superimposed on it.

In the next photo I’ve added labels showing my take on right/left and front/rear. If we start at the beginning of the whole sequence, the animal was trotting (those tracks aren’t seen in the photos) and then slowed down to a walk (the first three tracks in the distance shot). The next section shows that the fox slowed even more to an overstep walk (the first four prints in the photo below), then slowed even more to an understep walk. There’s an extra right hind that’s puzzling, but I’m guessing the fox just repositioned its right hind foot. Then the overstep walk reappears after which the fox picked up the trot (the two impressions at the lower right in the first photo). Notice that the step lengths in the overstep part are shorter than the regular walk steps that preceeded them, and the step lengths in the understep part are shorter yet.

That analysis was rather involved, but it leads to a picture of what the fox actually did. As it trotted along something it detected made it slow down, first to a walk and then almost but not quite to a standstill. It was probably sniffing and listening intently as it moved very slowly. Once the animal concluded that it was okay to move on, it resumed its journey at a trot. It’s impossible, without more evidence, to know what caused the fox to react the way it did. It may have been a threat, but it could also have been something that interested it for a different reason. It is, after all, mating season for wild canines.

And the fox I was following was definitely tuned in to mating season. Farther on I found a spot (shown in the next photo) where the animal had detoured to urinate on a small spruce branch. If you look in the center of the frame you’ll see a squiggle of urine that runs horizontally from the upper edge of the spruce branch. Because the urine wasn’t squirted out the side of the tracks we know this was a female. She would have lifter one hind leg forward and supported herself on the other hind leg (plus two front legs) as she urinated. The relative depths of the tracks tell us that the supporting rear foot was the left. Its track is in the prominent double impression above and to the left of the urine.

I’ll never know what made the gray fox slow down and leave the pattern discussed in the beginning of this article. It could have been a threat–there was certainly a coyote in the neighborhood, or it could have been the mountain biker. A fisher (whose tracks I also found on that day) would have made the gray fox nervous. And there were red fox trails as well. But the trail shown in the photos above doesn’t suggest alarm so much as cautious interest. The fox didn’t change direction but just continued on. Was it another gray fox, one she was familiar with, or one she had mated with in a previous year? We have a small part of the whole story, and we can only speculate about the rest, but it’s fascinating just as it is.

Mouse Maneuvers

The mouse–not most people’s favorite creature, to put it mildly. Certainly the house mouse can be a serious pest, but wild mice are different creatures altogether. To start with, they are more attractive than the drab house mouse, as you can see from the portrait of a white-footed mouse which heads this post. The white-footed mouse is one of two species which inhabit the northeast, the other being the deer mouse. They are closely related (both belong in the genus Peromyscus) and are so similar they can’t be distinguished from tracks or sign. Habitat may indicate which one we’re dealing with, but from the tracker’s perspective it’s not really important, since they have similar characteristics and behaviors. White-footed mice prefer deciduous and mixed forests at low and moderate elevations. The trails shown below were most likely made by deer mice, which are more common in boreal and high elevation forests.

Both deer and white-footed mice are hunted by just about every predator in our region, so they stay hidden whenever they can. In warm months they find safety within woody debris, shrubs, blowdowns, rocks, log piles, and sometimes human structures. In winter, snow usually provides ample cover. Mice are able to tunnel through snow if it’s not too dense, and deep snow actually contributes to their survival. Within a deep snowpack the temperature is highest at ground level and decreases toward the surface. The temperature gradient causes ice crystals in the lower levels to sublimate and recrystallize at higher levels, leaving spaces where small animals can find safety and warmth. Hollows at tree bases, among rock outcrops, and under downed logs and branches allow mice to move between the surface and the lower regions (the subnivean zone). That’s why the trails in the photo above radiate from the base of the tree at the upper edge of the photo.

The next photo shows a steep, snow-covered embankment at the edge of a groomed snowmobile trail. A mouse (it could have been either a white-footed or a deer mouse) bounded from the lower left across the packed snowmobile trail toward the slope. The mouse turned to the right and then went under a slight overhang where it found (or dug) a tunnel leading to safety in the deeper snow bordering the snowmobile trail.

Look under the log in the next photo and you’ll see mouse trails. Notice how the mouse trails run into (or out of–or both) the cavity at the upper left, a mouse-sized hole at the lower right, and unseen openings under the lower part of the log. As long as these openings are maintained, mice can move easily between the snow surface and the subnivean realm. The log also provides protection from aerial predators.

In soft snow mouse trails on the surface often lead to holes that connect to tunnels deeper in the snow.

Both deer and white-footed mice store nuts and seeds in cavities in logs, standing trees, and rock piles. Once winter comes any space protected by deep snow makes a good feeding area. The midden of black cherry seeds in the next photo shows where a mouse fed beneath the snowpack at the base of a tree. The neat round holes are reliable indicators of mouse feeding.

Mice use logs as travel routes, but we only see evidence of this when a light covering of snow coats the log surfaces. In the photo below you see a jumble of mouse tracks, a few of which show toes clearly enough to reveal the direction of travel. There’s a rear print at the lower left that points toward the left, and you can see a few front tracks near the upper edge of the snow with toes pointing toward the right.

There are other small mammals, voles and shrews in particular, whose trails can be confusingly similar to those of deer and white-footed mice, especially when they are bounding. But the bounds of voles and shrews are less regular and have more variable foot placement than the bounds of mice. Voles and shrews also use a greater variety of gaits than mice, including walks, trots, bounds, and lopes. Voles especially are likely to make frequent gait transitions, and often use a perplexing gait sometimes described as a shuffle. Mice can walk but it’s rare, and I’ve never seen evidence of a mouse trotting, shuffling, or loping.

Deer and white-footed mice are relatively long-legged and athletic, and they sometimes make long leaps. Voles and shrews, with their chunkier bodies and shorter legs, can’t jump nearly as far. So if you find a trail with leaps like those in the photo below, you can confidently assign it to a mouse rather than a vole or shrew. The tail marks are another clue. Mice have tails as long or longer than their body length. Both the short-tailed shrew and the woodland vole, the two species most likely to be confused with deer and white-footed mice, have very short tails and wouldn’t leave long tail marks like the ones in the photo.

The white-footed mouse trails in the next photo show the typical consistency of pattern and leap length, but the one on the left demands a second look. It begins at the bottom, a little to the right of center, goes upward for a few leaps, and then takes a hard turn to the left. After a few more leaps the trail circles back to the right and proceeds toward the top of the photo where there’s a fallen branch sticking out of the snow (just outside the frame). Each time it turned the bounding mouse flung its tail to the outside for balance, leaving conspicuous tail marks. There’s a pile of snow that was kicked toward the rear where the mouse turned left, and where the trail curves back toward the right the landing/takeoff depressions are deeper. These observations suggest extreme bursts of energy.

We’ll never know for sure, but the most likely explanation is that a threat spooked the mouse. There’s no sign of an actual attack, so the mouse evidently survived, but it must have been alarmed by something. Deer and white-footed mice, along with other small rodents, are in constant danger of predation, and we sometimes find evidence of a successful hunt (see my post for March 1, 2022). But most of the time mouse trails tell us they survived to live another day.