Category: animal tracking

Streamside Discoveries

As the high water levels of late winter and early spring subside, stream and lake margins become interesting tracking locations. Water is a magnet for wildlife, and visiting creatures leave the evidence of their activities along the shoreline. A great blue heron left the collection of tracks shown in the photo below. The feet of herons resemble the feet of songbirds, with one backward-pointing toe and three forward-pointing toes. But unlike most songbirds, the toes of herons don’t all meet at one point. There’s a left print (facing toward the lower right) in the upper left corner of the photo that shows this nicely. The junction between the backward-pointing toe and the inner forward-pointing toe lies to the left of the intersection between the two outer toes. Another way of saying this is that the two outer forward-pointing toes join a little to the outside of the center of the foot. The same asymmetry shows in the right track in the lower right corner.

The spotted sandpiper is another bird that patrols stream and lake margins. These small birds–about the size of a starling–search for invertebrates on the edges of streams, ponds, marshes, and other bodies of fresh water. Their tracks (shown in the next photo) reflect their erratic and meandering movements. The three forward-pointing toes are relatively symmetrical and diverge at wide angles. On the back of the foot there’s short spur oriented to the inside that may or may not make an impression in tracks. The left print just below the stick in the upper right corner shows the spur nicely.

Raccoons prefer comfortable surfaces so it’s no accident that the animal that left the tracks shown in the photo below stepped along a soft deposit of sand left by a recent flood. The raccoon moved from the upper right to the lower left, leaving tracks in the sequence right rear, left front, left rear, right front. The difference between the wider but tighter rear track and the narrower, more spreading front track is easily seen in the set of prints at the upper right. Raccoons habitually work the edges of streams and ponds where they find tasty shellfish, frogs, crayfish and other invertebrates. The pattern of alternating sets of hind and front tracks from opposite sides tells us the animal was moving at a pace-walk.

Mink are also in the habit of travelling along the margins of water bodies. The animal that made the tracks in the next photo was moving from right to left at a lope, and the track sequence is right front, right rear, left front, left rear. Like raccoons, mink have five toes on both front and rear feet, but it’s not uncommon for the impression of the inner toe to be missing. In fact the only print in the photo that shows a clear inner toe is the left front. This track also shows the middle pad protuberances (just behind the toes) and the heel pad (the small indentation behind the middle pad). Mink share a taste for crayfish, frogs and invertebrates with raccoons, and occasionally catch small fish. They’re adaptable predators and may also hunt for small mammals on the surrounding land.

The mink’s larger relative, the river otter, also leaves its tracks along the edges of ponds and streams, but for this creature it’s mainly a matter of convenient travel between feeding areas. I found the tracks in the photo below on the inside of a bend in a stream where an otter had taken a short cut across a large sandbar. The sequence of tracks is the same as that of the mink tracks in the previous image, and the family resemblance–both mink and otters are mustelids–can be seen in spite of the different substrates. Otters are more aquatic than mink and capture most of their food in the water.

When they’re not foraging in the water otters spend their time on conveniently accessed sites near the water. They roll on soft surfaces like grass and forest duff to clean and dry their fur, and they socialize with other members of their family group. They also leave notices in the form of scat to non-resident otters that the territory is occupied. The otter scat in the photo below contains crayfish shell fragments, but it’s also common to find scats containing fish scales and bones, or the slimy remains of frogs. Otters often use latrines where scat of various ages and contents can be found.

The beaver is another very aquatic mammal. In the photo below you see two beaver tracks, a right front (above) and a right rear (below), both facing toward the right. In the front track the four toes show clearly and the two heel pads appear as elongated grooves because the foot slipped in the mud. In the bottom part of the frame the three outer toes of the hind print show clearly but the two inner toes are obscured by the front print. As is often the case, the webbing of the hind foot doesn’t show. The size difference between the front and rear tracks is striking and helps us to understand why beavers are such strong swimmers. Beavers feed on the leaves, bark, and stems of woody plants year-round, but during the growing season the diet also includes aquatic plants, cattails, sedges, and forbs. Their tracks usually lead between the water and foraging sites on land, and signs of branches being dragged into the water are common.

Smaller–but just as well adapted to life in water–is the muskrat. Like the beaver, the muskrat has rear feet that are much larger than the front. In the photo below, the track farthest to the left is the right rear, and just to its right you see the right front. On the right side of the frame the left rear lies below the left front. Notice that the small inside toes of the front feet made impressions in both of the front prints. The muskrat’s front feet, like those of the beaver, are adapted for handling food items and building materials rather than for swimming.

If you wander along shorelines you may find muskrat latrines. These sites are usually located on logs or rocks that lie in the water but protrude above water level. In the next photo you can see a rock decorated with scat of varying ages, deposited as an announcement that the territory is occupied. Although muskrats occasionally consume animal foods they are primarily plant eaters, and their scats usually contain fibrous material.

This is just a sampling of some of the wonders to be found along the margins of lakes, streams, and marshes. There’s always something to be discovered, so next time you’re out and about, take a detour to check a stream edge or a muddy shoreline. Better yet–if you don’t mind some wading–try a stream walk. It could be just the thing on a summer day.

Mud, Glorious Mud!

Unlike many people I know, I’m always sad to see the snow disappear for good. But as soon as I think of what comes next–mud season–I get excited all over again. The transition between the seasons is highlighted in the photo below. A gray fox had stepped in some mud and then left it’s muddy footprints on the snow as it walked from left to right. Each deposit of mud is made by first the front and then the rear feet from the same side, and the zig-zag pattern of the walk shows nicely.

Once the snow is gone, ordinary mud takes its place as a medium for recording tracks. In the next photo an opossum stepped in some mud at the edge of a puddle, leaving a collection of both complete and partially obscured prints oriented toward the left. At the upper left there’s a right front track with a right rear track just behind it. Farther to the right you can see part of another right front track. In the lower right corner there’s a nearly complete left front print and just the suggestion of a left rear behind it. The front prints show the five widely spread toes that are characteristic of the opossum. In the front print at the upper left the segments of the semicircular middle pad are especially clear. The rear track in the upper center shows the strikingly different form of the opossum’s rear foot: a thumb-like inner toe pointing inward and four additional toes close together and pointing outward.

One of the nice things about mud is that it can record the presence of animals that we don’t encounter during the cold season. A spotted salamander (or maybe two of them) walked through the mud in the next photo. These amphibians hibernate in winter and come out in early spring, so mud season is a good time to look for their tacks. There are two trips: one going from the left side toward the upper right and the other proceeding from left to right along the lower part of the frame. Each trail consists of a central drag mark made by the tail and a sequence of front and rear prints on each side. The patterns of the prints tell us that the animal(s) were moving at an understep walk, with each rear foot touching down just behind the front foot from the same side. In the lower trail you can see the difference between the smaller, four-toed front prints and the larger, five-toed hind ones.

The tracks in the preceding photos are pretty obvious, but it’s not always easy to spot tracks in mud. In the photo below there’s a patch of shiny mud in the center of the shot, and on the right side of that patch there are some tire tread marks. If you look on the left side of the same shiny mud toward the top you’ll see a red fox track. The animal was moving from top to bottom, and because there weren’t many muddy spots the print in the photo was the only one I could find.

The close-up below shows the same track, but in this view it’s oriented in the opposite direction, toward the top. The central mound typical of canine tracks can be seen, and the marks made by the hair on the underside of the foot show clearly. There’s even a partial impression of the bar in the middle pad.

Woodchucks, like salamanders, spend the winter below ground and often emerge just as mud season is beginning. The next photo shows the left rear track of a woodchuck at the upper left and a left front track at the lower right. The five clawed toes of the rear print show clearly–the middle three toes set close together and the inner and outer toes angled toward the sides. Behind the toes you can see the four segments that make up the middle pad. In the front track the four toes with their substantial claws can be seen. The subdivided middle pad of the front foot lies behind the toes, and the heel pads show as two depressions behind the middle pad. The front print has a curvature toward the inside, a trait typical of the woodchuck.

It takes a medium with a fine texture to show details of the tracks of very small animals, and what better medium than mud? In the photo below you see the tracks of a white-footed mouse bounding from lower left to upper right. The tracks are arranged in the typical rodent bounding pattern–two rear prints (in the upper right quadrant) that are widely set and almost even with each other. Behind the rear tracks, the front prints are set more narrowly and, in this case, slightly staggered rather than even with each other. Track details show beautifully, especially in the left rear (the topmost track) and the left front (farthest to the left). If we compare these tracks with the woodchuck tracks above we see the rodent family resemblance, especially in the rear prints. The symmetrical mouse front tracks are more typical of other small rodents than the curved front prints of the woodchuck.

You can’t ask for a better rendition of detail than the porcupine tracks in the next photo. Porcupines have unique foot anatomy: their tough, undivided soles have a pebble-like texture that gives the animals good grip when climbing. The photo shows a left front print and, just behind it and overlapping slightly, a left rear print. The tracks are heading toward the left, and the texture of the soles shows beautifully. Because the leading edge of the rear foot touches the trailing edge of the front track, the two tracks seem to be joined together. You may be able to pick out the claw marks of the hind print along the leading edge of the sole of the front print. The four claws of the front foot made indentations at the very left, and if you look closely there are marks made by the three outer phalanges of the front foot behind the claw marks.

Once the snow melts and the weather warms, mud may not last long. Puddles may dry up and wet areas may fill in with plant growth. But mud can also appear in new places, and abundant rainfall can bring on new mud seasons long after the early one is over. As a matter of fact, I found the porcupine tracks in the photo above in the month of July. So keep an eye on the conditions of the puddles in your neighborhood, and don’t be surprised if you come across some beautiful mud when you least expect it.

Cottontail Rabbits

Familiar animals can be just as interesting as less common ones, and the cottontail rabbit ranks as one of our most familiar–and interesting–creatures. In the photo below (direction of travel from right to left) we see it’s characteristic Y-shaped bounding pattern: two rear tracks even with each other and widely spaced, and two front tracks behind the rear ones, more narrowly spaced with one leading the other. The right front print (the first foot to come down) lies at the right side of the photo and the left front print (the second foot to come down) lies to its left. Farther to the left you see the rear prints which form the diverging branches of the Y. I found these tracks on a highly developed barrier island on the New Jersey coast, probably not a place you would expect to find cottontails. But these animals manage to survive and flourish not just in rural and undeveloped areas but also in city parks, suburban communities, and busy commercial zones.

Although the pattern shown above is very common, it’s not the only four-print arrangement you’ll see. Sometimes a rabbit’s front feet come down together, and when this happens the prints are even with each other and pressed tightly together. Bounding squirrels make groups similar to those of rabbits, but the spacing of the front tracks is different. Whether the front prints are even with each other (the most common arrangement) or whether one leads the other, there is almost always a gap between the two prints. In the photo below the rabbit tracks are in the lower left and the squirrel tracks are at the upper right.

The tracks in the photo below were made by a cottontail bounding in deep snow (direction of travel from bottom to top), and the toes are splayed out in both front and rear tracks. Tracks like these are sometimes mistaken for snowshoe hare tracks because of their larger size.

The feet of both cottontails and snowshoe hares can spread when increased support is needed, but there’s a drastic difference between the two animals. The maximum width of a cottontail’s hind print is about 2 1/2 inches, while a snowshoe hare’s rear track can reach a width of more than 5 inches. The photo below shows a rabbit’s rear foot (seen from the bottom) in a splayed position. Note that the rear foot has only four toes.

In the photo above you can see the thick fur which covers the bottom of the rear foot of the cottontail, and the front foot is just as furry. This is why the outlines of the toes in rabbit tracks are blurry, especially in snow. The next photo shows the right front print of a cottontail (facing to the right) in mud that had dried to a perfect consistency for recording fine details. The toes are visible but not sharply defined, and the texture of the fur can be seen in and around the toe impressions. This photo also shows all five toes clearly–yes, there are five toes on the front foot of the rabbit. But counting toes can be difficult because there are also some pads which look like toes.

To help sort this out I’ve marked the toes and two of the pads in the next photo. The innermost toe is marked Toe 1, following the convention of numbering from the inside of the foot. It’s smaller than the others and often fails to register in tracks. The other four toes are larger and tipped with substantial claws, and the toe arrangement as a whole is asymmetrical.

If you’ve ever had a run-in with a rabbit’s foot you know that, in spite of the furry covering, the sharp claws can dig in quite effectively. Sometimes the claws are the only parts of the foot that make impressions, as in this photo of the right and left rear tracks of a rabbit in a hurry (direction of travel toward the upper right).

In addition to tracks, rabbits leave many other signs of their presence. You may find stems bitten off at an angle like the multiflora rose in the photo below. These angled cuts are characteristic of rabbit browsing and they arise from the anatomy of the rabbit’s jaws.

In the next photo you see the lower jaw of a cottontail with an added line representing a stem or twig. As it takes the stem between its upper and lower incisors, the rabbit positions the stem so that one end passes through the gap between its incisors and its molars. This biting technique results in an angled cut. Deer don’t have upper incisors so instead of making a clean bite, a deer grasps the stem between its lower incisors and its horny upper palate and pulls or jerks to make a rough break.

Cottontails also feed on the bark of young trees and shrubs. Their chews have a rough appearance, with bites penetrating to varying depths, as in the staghorn sumac stem shown below. Chews made by other bark feeders (beavers, porcupines, voles, and occasionally squirrels) are much neater and more consistent in depth of penetration.

Whether it’s bark, twigs, or buds, a rabbit has to ingest a lot of fiber to get at the nutritious living cells in the cambium or in the tiny leaf initials inside buds. The animals boost the nutrition they get from their food by processing it twice. After passing through most of the digestive system, waste is diverted to the caecum where it is fermented to produce additional nutrients. This material is eliminated, usually at night, as clusters of soft globs called caecotropes. We seldom see this kind of fecal matter because the rabbit eats it immediately. After passing through the digestive system again, the waste is eliminated as pellets like the ones in the next photo.

These pellets are dry and fibrous, and are normally scattered irregularly where rabbits feed and move about. Unlike the rounded cylindrical pellets of deer, rabbit pellets are shaped like slightly flattened spheres. Cottontails are now shifting to their summer diet of grasses, forbs, and flowers, but the final result will be pellets similar to those produced from woody food.

The cottontail rabbit is a thoroughly interesting creature with some impressive tools for survival. By observing its tracks and trails as well as chews, scat, and other sign, we can appreciate a creature that is beautifully adapted to its environment.

Raptors on the Hunt

Many birds of prey (especially buteos and larger owls) depend on small mammals for much of their diet, and snow can record dramatic encounters between predator and prey. We see such a story in the image above: the trail of a white-footed mouse ends abruptly where it was snatched by a raptor. The mouse was bounding from the left, and the bird hit it a little to the right of center, leaving a deep depression. Some light striations around the disturbance show where the bird’s wings stroked the snow. It’s hard to say with certainty whether the lucky hunter was a hawk or an owl, but there are a few observations that point to hawk. First, hawks hunt by sight, usually locating their prey on the surface, and that’s what happened in the clash shown in the photo. Owls usually detect prey by sound and often attack prey under the snow surface. Second, hawks tend to carry prey with their talons while owls take the victim in their beaks (although both deliver the killing wound with their claws). The disturbance where the mouse met its end doesn’t show signs of repositioning from talons to beak. A less reliable feature is the sharpness of the wing marks. Owl wing feathers have soft edges designed to reduce the sound of the wings, while hawk flight feathers have sharp, well defined edges. Under ideal conditions owl feather marks are more diffuse than those of hawks, but this feature varies depending on the texture of the snow. The wing marks in the photo are relatively crisp, so at the very least they don’t rule out hawk as the hunter.

In the next photo you see another attack on a mouse. This time the mouse trail enters from the right. The bird also came in from the right, and the deep disturbance where it hit the mouse tells of the violence of the impact. One talon made a gouge in the snow going down into the depression from the right, and both wings made marks on the left side of the photo as the bird lifted off.

A closer look reveals a spot of blood in the depression, visible in the center of the photo. It also looks like there was some repositioning, either in the talons or from talons to beak. The surface attack suggests hawk, but the repositioning tends more toward owl, and the feather marks could have been made by the softer feathers of an owl.

In both of the encounters I just described the hunter succeeded in capturing the prey, but in the photo below you see a different situation. The snow was deep and had an icy crust covered by about an inch of new snow. Sounds of an animal (most likely a white-footed mouse or a meadow vole) under the snow had drawn an avian predator, and the bird had hit the surface hard with its talons. The crust hadn’t yielded, and the only signs of the attack were the impressions of the talons and a few feather marks in the snow. This was definitely an owl since a hawk would not have detected prey hidden under the snow. And this time there’s additional evidence in the form of tracks. The K-shaped talon prints in the lower part of the photo indicate owl–probably a great-horned owl based on the field-and-hedgerow habitat. The feather marks in the upper right part of the photo give some insight into the variation associated with this kind of evidence. The left-most stroke is sharply defined but the ones to its right are less crisp.

In the next photo you see another attempt by an owl, this time in soft snow. Sounds of a small animal under the surface had drawn the attack, and the quarry had been able to evade the owl’s talons at least for a time. I wasn’t able to get close enough to look more closely, so I don’t know who came out on top of that struggle.

Many potential victims are never attacked (consider how often we find the undisturbed trails of mice and voles in the snow), and many that are attacked manage to escape. Estimates of hunting success vary widely, but the highest I’ve found is about 50% from a study of red-tailed hawks in Missouri. Other estimates go as low as 15%. And remember, this is the percentage of actual attacks that result in prey capture. Before an attempt is even made, a bird of prey must spend time hovering, soaring, or perching, in an effort to detect a potential prey animal. There’s a finely tuned balance between predators and their prey. Raptors display impressive hunting skills, and the small animals they prey on have effective ways of evading capture and high rates of reproduction. When we come across signs of a raptor attack we experience a vivid illustration of the complex interplay between predator and prey.

Canine Romance

It may seem like the wild creatures are all hunkered down, just doing their best to stay alive and wait out the cold season. But for wild canines there’s more going on than simple survival. This is mating season for foxes and coyotes, and they’re engaging in behaviors that will eventually lead to reproduction. For human trackers the first clue to their new fixation is the increasing frequency of scent marking. In the photo below you see a splash of urine on the snow to the right of the corn stalk, left as a message to others of its kind by a gray fox.

Urine contains complicated combinations of chemicals that, to a discerning canid, reveal the identity and health status of the animal that produced it. As mating season progresses, changes in the chemical signature also indicate the animal’s readiness for mating and reproduction. Most of these messages are too subtle to be detected by people, but fox urine is an exception. The urine of both red and gray foxes takes on an increasingly musky, skunk-like odor as hormonal changes progress, and in late winter this odor is strong enough for a person to detect it a good distance away from the deposit.

The fox whose scent mark is seen in the image above was walking from the upper left to the lower right. We know that the it was a male because of the placement of the urine off to the side of the animal’s trail. The direction of travel is revealed by the appearance of the snow around the edges of the tracks. When a foot goes down into snow it pushes any movable material down into the hole. When the foot comes up and out again it often brings a little snow up with it, and this snow is dropped around the leading edge of the track as the foot moves forward above the surface. This means that the snow around the entry end of a track is relatively undisturbed while the surface at the exit end is decorated with sprays or scatterings of snow. In the photo of the gray fox trail there are four deep tracks, each one the landing place of a front and a rear from the same side, plus a light track near the third deep track. Starting at the upper left (and considering just the deep tracks), the sequence is left front + rear, right front + rear, left front + rear, right front + rear. The animal was standing on its right hind foot when it lifted its left hind leg to squirt urine at the corn stalk. The shallow print was probably made as the fox placed its right front foot lightly on the snow for balance while it was urinating. The corn stalk was a convenient object, but rocks, clumps of weeds, branches, or anything else that protruded above the snow would have done as well.

Among coyotes and foxes, early winter is the time for the establishment or reestablishment of pair bonds. Those that spent time apart after they raised a litter in the previous season usually rejoin, and unattached animals roam widely in search of potential mates. Bonded pairs establish their territory by scent marking around the edges, especially along borders shared with others of their species. Unless we are familiar with the area and the animals involved it’s hard to know whether scent marks are advertisements of availability or warnings that the territory is occupied.

During the lead-up to mating, pairs often travel together. The trails in the photo below were made by two red foxes travelling along a forest road. For at least half a mile the two trails wove back and forth, occasionally changing speed and sometimes diverging, but always coming back together. The male, with slightly larger tracks, enters the frame at a gallop, moving from the lower left to the upper right. The female is doing a side trot and her trail comes in at the lower right and leaves at the top of the frame just to the left of the male’s trail.

All of the behaviors I’ve described above help to strengthen the pair bond and propel the hormonal changes that lead up to mating. When the female’s endometrial lining begins to develop, her urine contains blood, and she leaves scent marks like the one in the photo below. She’ll soon go into heat and only then will she be receptive to the male’s advances.

The pair are both involved in the process of den selection and preparation, and pups are born about 50 (foxes) or 60 days (coyotes) after successful coupling. By initiating the early stages in the dead of winter nature insures that the pups are born in the spring when food will become increasingly abundant. Note: It’s important for trackers to avoid disturbing animals during this vulnerable time. We should not approach too closely or otherwise disturb a den site starting with the period of den preparation and continuing until the pups are no longer dependent on the den for safety.

This is, by the way, why coyote-dog hybrids aren’t as numerous as some people believe. Over thousands of years of domestication, dogs have lost the finely tuned sequence of reproductive behaviors that occurs in wild canines. Mating in dogs is no longer synchronized with the seasons, and males don’t assist in the raising of pups. Since these behaviors are genetically controlled, the offspring of matings between dogs and coyotes have disrupted patterns of behavior. The precise timing of reproduction is lost, as well as the strong pair-bonding and the dual effort from both parents (and sometimes female offspring from the previous year). For this reason the offspring of matings involving dog-coyote hybrids are unlikely to survive.

This is a great time of year to let tracking open a window into some of the underlying processes of the natural world. The mating rituals of wild canines have been shaped for success by natural selection, and this is beautifully illustrated in the behaviors we see in the tracks and trails of foxes and coyote.

When Trails Cross

Was the fox afraid of the fisher? Did the coyote chase the rabbit? Questions like these often come up when we find animal trails that intersect. And as always, the tracks tell the story. In the photo below a coyote trotted along a forest road, the direction of travel from upper left to lower right. A rabbit bounded across the road, leaving a trail heading from right to left. Both trails had been made early on a cold morning, and I came upon them not long afterwards. Neither trail showed any changes in pattern or speed in the vicinity of the intersection (although the rabbit took a few slow hops as it entered the road). The tracks in the photo tell us that whichever animal came second, it wasn’t alarmed or excited by the trail it was crossing.

Here’s another example: A coyote had trotted from upper right to lower left, and at least a day later a fisher loped from lower right to upper left across the coyote’s trail. The unchanging pattern of the fisher trail tells us that it had no apparent reaction to the older coyote trail.

In the next photo you see another instance of a fisher crossing a coyote trail. The coyote was trotting towards the upper right, and the fisher loped from right to left. But this time the tracks near the intersection reveal a definite reaction on the part of the fisher. The change in rhythm and the extra tracks tell us that the fisher was very interested in the coyote trail.

Parsing out all those extra tracks is tricky, but you can see my interpretation of the encounter in the next photo, a close-up in which I’ve labelled the tracks. The coyote trail is a nearly straight sequence of tracks on a rough diagonal from lower left to upper right, and its tracks are marked as CL F+H, CR F+H, etc. The fisher tracks are labelled RH, LH etc. Starting at the lower right there’s a right rear track from the fisher’s loping approach, and to the left of that track there’s a group of five prints. Four of those tracks make up a shortened lope pattern and the fifth sits above them and points toward the eventual continuation of the fisher’s journey. The tracks closest to the coyote trail show how the fisher paused and did a thorough examination. Apparently satisfied with its inspection, the fisher continued loping in the original direction.

Why was the fisher so interested in the coyote trail? A coyote would represent a danger to a fisher. A fight between the two could cause the fisher’s death and also pose needless risk for the coyote. But encounters between predators rarely happen because they keep tabs on each other’s movements. The tracks would have revealed the identity and nearness of the coyote, and the fisher apparently decided that it wasn’t in any danger.

I found the coyote tracks in the next photo on a sunny morning following an overnight snowfall. I must have been there not long after the coyote came through, since its tracks didn’t show any signs of melting. The coyote walked from right to left, changing its direction as it crossed an otter trail (which also showed no signs of melting) but otherwise taking little notice of the mustelid’s slide.

I continued to follow the coyote trail and soon came upon a spot (shown in the next photo) where the animal had encountered several pheasant trails. The pheasants had been there earlier in the morning before the sun had risen above the distant trees. The snow would have been several inches deeper, and the pheasants would have dragged their feet through it. Once the sun rose higher it began to melt the snow. By the time I came along the depth of the snow had been reduced and the pheasant tracks had been transformed into a series of pits connected by a raised, wavy ridge. How did this happen? Disturbances created by footfalls create slightly denser snow around–and between, if the feet drag–tracks, and denser snow melts more slowly than undisturbed snow. The compacted snow around and between the pheasant prints sank down more slowly and was transformed into the raised ridge. The coyote came along shortly before my passage, so its tracks hadn’t been exposed to the sun for very long and were unaltered. As the coyote investigated the pheasant tracks it left a jumble of prints, but it probably decided the birds were already far away and not worth pursuing.

So why did the coyote react differently to the two trails it crossed? The otter trail was more recent, judging by the lack of alteration, but a powerful animal like an otter would not have been seen as potential prey by a coyote. A pheasant, on the other hand, would provide a welcome meal for a hungry predator.

Signs of interaction when creatures cross paths may not be as obvious as the examples I’ve described above. You might just see a lighter track a little to the side, made as an animal paused before continuing on. Or differences in speed or gait may reveal an awareness of the recent presence of another creature. Whatever the reaction, it will always be transmitted through the animal’s feet and written in its tracks. Reading those tracks opens a window into the life of that animal.

Dog Tracks: Common But Not Always Commonplace

Our familiar companion animals leave their tracks everywhere, and we see them so often we may find ourselves giving them only superficial attention. But if we look more carefully we may be surprised at how much they have to teach us. Dog tracks can show us the traits that are shared among dogs and their wild relatives, and they can also reveal the remarkable range of variation that could only belong to a long-domesticated animal.

The photo below (direction of travel toward the top) illustrates a number of core features that are shared by dogs, foxes, coyotes and wolves. The front track (lower left) is larger than the rear track (upper right). Both front and rear tracks have four toe impressions, and a single smooth middle pad. The tracks are symmetrical, meaning that if an individual track were divided down the middle and the right half were folded over onto the left half the two halves would superimpose almost perfectly.

There are a few additional traits in these prints that are shared among some–but not all–dogs and their wild relatives: The overall outlines of both front and rear prints are oval, the toes are held tightly together, and the claw marks point straight ahead. The larger ridges between the toes and the middle pad form the celebrated canine X, and the center of each track is occupied by a rounded dome or plateau. But although the tracks are roughly coyote sized, we see several additional traits that indicate dog rather than coyote. The claw marks are wide and deep, the middle pad of the front print is large compared to overall size of the track, and its trailing edge is rounded.

A comparison between the dog tracks above and the coyote tracks in the next photo will highlight the differences. (The coyote front print is below and a little ahead of the rear, and the direction of travel is to the right.) Like the dog tracks, the coyote prints are compact, with oval or egg-shaped outlines and tightly held toes. But some of the claw marks are missing, and those that are visible are delicate rather than robust. The middle pad of the front track is relatively small, and its trailing edge is concave.

The dog front track shown in the next photo is even more of a departure from the two preceding illustrations. Instead of being oval the print is round in outline, and the toes, especially the inner and outer ones, are widely spread and angled to the sides. The upper arms of the canine X seem to have been pressed apart, and there’s a curved ridge instead of a dome at the center of the track. Like the previous dog tracks, the print in the photo below has wide claw marks and a large middle pad. A track like this is easily recognizable as dog.

The photo below shows another dog track variant. The overall outline is rounded–in fact the print is a little wider than it is long. In contrast to the triangular middle pads of the previous dog tracks, this print has a trapezoidal middle pad with a broad leading edge. Instead of an X the internal ridges form a distorted H shape, and there’s a horizontal ridge rather than a dome in the center of the track. The absence of claw marks is unusual for a dog print. This is the kind of track that might be mistaken for a feline–a house cat, bobcat, or even a cougar depending on the size of the print. But there are clues that indicate dog, and they become obvious if we look at a true feline print.

The photo below shows the right front track of a bobcat. If we test for symmetry using the folding test described in the second paragraph, we can see that the dog track above is symmetrical and the bobcat track below is asymmetrical. There’s a leading toe (second from left) and a trailing toe (rightmost) in the bobcat print, and the middle pad is canted to the right. Instead of the canine X we see an angular C-shaped ridge that is also canted to the right. Another important feline trait is the contrast in size between the large middle pad and the small toes.

Wild canines have a way of placing their feet quietly, without tension or unnecessary movement. Dogs, on the other had, often express slight jiggles or shifts in the movements of their legs, and the difference can sometimes be seen in their tracks. In the photo below you see two dog tracks (in the upper left, the front a little below and behind the rear) and two coyote tracks (the front in the upper right corner and the rear just below the two dog tracks). Displaced bits of snow lie inside and around the edges of the dog tracks, while the coyote tracks have mostly smooth floors and margins. The best way to see the action that produces this kind of difference is to watch a dog walking or trotting directly away from you. You may see subtle shifts in the body or slight wobbles as the legs contact the ground.

Dogs lead easy lives compared to wild animals, and this often shows in the trails they make. The tracks of three creatures can be seen in the photo below. A dog meandered from top left to bottom right, leaving two partly superimposed tracks in the upper left corner, two tracks close together midway down the left side, and two more widely separated tracks at the lower right. A coyote trotted from top to bottom leaving smaller direct register prints, one between the dog tracks in the upper left and another at the lower left. And my boot tracks can be seen to the right of the dog tracks.

Wild creatures cannot afford to waste energy. There are exceptions: young animals play, and during mating season mature animals can make some wacky moves. But the business of survival demands efficiency of movement. Dogs, on the other hand, can expend energy without the pressure of finding their next meal. The coyote in the photo above had a destination in mind and moved with purpose. The dog was well fed and carefree, and counted on finding food and shelter when it got home. And I was focused on the story those tracks told about the lives of dogs and and their wild relatives.

Buck Rubs

Autumn is mating season for white-tail deer. The bucks sport fully formed antlers and bulked up necks and shoulders, and they’re busy sparring, posturing, and otherwise asserting their suitability as mates. Antler rubs are an important part of the bucks’ demonstrations. To make a rub a buck approaches a sapling or small tree and works its antlers up and down against the trunk. The rough surfaces at the antler bases act like rasps to remove the bark, and the tips of the tines leave rough gouges. In the center of the rub the exposed wood is bright and relatively smooth, and dislodged bark fibers may hang from the roughened margins.

Buck rubs are only made on living trees, and vertical trunks that have an unobstructed approach are preferred. Buck rubs are generally located between 1 and 3 1/2 feet off the ground and can be found on both hardwoods and conifers up to 10 inches in diameter. The light color of the exposed wood is eye-catching, but the most important part of the message is invisible. The buck deposits chemicals from scent glands in its skin by rubbing its forehead against the surface of the rub. In the process of making a rub a buck stops periodically to sniff the surface. Later, visiting does sniff the rub and take in olfactory messages that reveal the health and status of the rub maker.

Contrary to common belief, buck rubs are not connected with the removal of the velvet, the highly vascularized tissue which nourished the antlers as they grew. By late summer the rack is fully formed, and the velvet is beginning to wither and slough off. This process is assisted when the animals thrash their antlers against shrubs and small trees. By the time the rut begins in earnest the velvet is long gone.

An individual tree may be hit more than once, and a popular one may take on a whimsical appearance. Damage like that shown in the photo above may be enough to kill a young tree.

Rubs from previous years are often found among fresh rubs. Old rubs like the one in the photo below are dulled by weathering and are usually rimmed by callus formed in the growing season following the assault as the tree attempted to heal the wound.

Other animals also remove bark from woody plants, but there are usually clues that help to identify the culprit. Squirrels strip bark from stems and branches to use for nest lining, and stripped stems can look similar to buck rubs. Dead trees or branches are often the source for squirrel nest lining, and in that case we know it can’t be a buck rub. But sometimes the bark fibers are harvested from a living tree or shrub, such as the honeysuckle in the photo below. The lack of abrasion on the debarked area and the undamaged hanging strips signal squirrel rather than deer. Squirrels can gather fibrous bark from stems at any height, and the debarked areas in the photo are closer to the ground than an antler rub would be. If nearby stems or branches obstruct the stripped stem it’s also unlikely to be the work of a deer. And finally, as in the photo, stems harvested by squirrels may not be vertical while buck rubs usually are.

Debarking can also be a result of chewing. In the photo below you see a stem fed on by a cottontail rabbit. The irregular removal of bark and outer wood differs from the vertical bands left by the up and down rubbing of an antler. Rabbit feeding is also usually closer to the ground than would be expected in an antler rub, but keep in mind that deep snow can result in elevated rabbit chews. Porcupines and beavers also chew on shrubs and trees at varied heights. But like the rabbit chew, the tooth marks left by these animals are different enough from the abraded surface left by antler action to separate their chews from buck rubs.

Antler rubs are part of a suite of behaviors that allow male white-tail deer to establish dominance and demonstrate their prowess, but that’s not all there is to it. These behaviors also trigger changes in the females that prime them for mating. Sniffing a rub sends chemical signals to a doe that precipitate a flood of hormones and prepare her for reproduction. Buck rubs are part of an intricate interplay of behaviors that results, if things go well, in the appearance of offspring about 6 1/2 months later.

Beavers at Work

Some animals live among us almost undetected, and others leave evidence that is obvious and long-lasting. Beavers are a good example of the latter, leaving signs of feeding on woody plants and creating dams and lodges that may last for years. The featured photo shows a lodge made of mud and sticks and surrounded by protective moat of water. What we can’t see is the underwater entrance which leads upward to a dry, multi-level living area. In the upper left quadrant of the photo there’s a dam, seen from the upstream side. The freshly peeled sticks that decorate the lodge and the dam, and the water lapping right up to the top of the dam, indicate that there were beavers in residence when the photo was taken.

Beaver dams can be impressive structures. The next photo is a view of a dam from the downstream side. The heaped up sticks conceal inner layers of mud interlaced with more sticks. Beavers react to the sound of flowing water, and any leaks are plugged with mud and more sticks. As long as the dam is maintained, the water level stays high enough to keep the lodge (not seen in this photo) secure in its watery surroundings.

A little exploration around the edges of an active beaver colony will turn up additional signs. When whole trees are removed the only thing left may be a chewed stump like the one below. Wood chips scattered nearby show where branches were removed and the trunk was sectioned and dragged off.

Some logs may remain where they fell, but they seldom go unused. One such log is shown in the next photo, and it’s a nice demonstration of the beaver’s chewing technique. The horizontal row of small cuts along the edge of the bark shows where the upper incisors were anchored. The vertical grooves in the lower peeled part of the log were made as the lower incisors were drawn up toward the anchored upper incisors. And why all this chewing? To get at the living cambium cells, located between the wood and the outer bark. Although there are exceptional cases where other food is available (such as the rhizomes of water lilies), most beavers depend on the cambium of woody plants for survival when leafy vegetation isn’t available.

Many dams and lodges are used for several years in succession, and newly added sticks and branches stand out against the mud and older sticks. The residents of a beaver colony also create deliberate messages indicating their claim to the location. In the photo below you see mud that was dredged up from the bottom and deposited on top of a grass hummock to create a scent mound. Whatever is handy at the edge of the pond, whether it be mud, muck, or rotting vegetation, can be dredged up and carried to the shore to make a pile. The final touch comes when the beaver drags its anus over the mound and deposits urine and secretions from its anal glands and castor sacs. The smell is not unpleasant, but it’s hard to describe. It reminds me of a horse barn, but it has also been compared to musk, human sweat, cheese, fruit, leather, birch beer, or some combination thereof. Scent mounds are most often created in spring, and the distinctive odor can persist for weeks.

If ponds and small streams aren’t available, beavers take up residence in creeks and rivers. But these habitats are subject to regular flooding, and the volume of flow during high water would destroy dams and lodges, so river beavers make their homes in the stream banks, digging underwater entrances and excavating living spaces above water level. If beavers are living in a river you may find peeled sticks, cut stumps, and scent mounds along the riparian margin. Another good clue is tracks in silty or muddy stream margins.

The tracks in the photo below were made by a beaver walking from lower right to upper left. The large hind prints make a wide zig-zag, starting with the left rear in the lower right corner. As in other four-footed walking trails, there are two footfalls–a front and a rear from the same side–at each zig or zag, but the front prints are mostly covered by the larger rear prints. All, that is, except for the two tracks at the upper left. The larger print above is the right rear, and next to it, just below, is the much smaller right front. Some of the rear prints may remind you of the tracks of a large bird. That’s because beavers often touch down lightly or not at all with their two inside toes, so the outer three toes make the most prominent impressions. But the heel marks behind the toes (as well as the wide palm areas at the bases of the toes) tell us it was a beaver, not a bird.

Whether they’re pond beavers or river beavers, at some point the animals will have exhausted the local food supply and will be forced to relocate to a better situation. If dams and lodges are not maintained water levels will fall. Chewed stumps and peeled sticks will weather to dull gray. Even though they aren’t fresh, these signs will persist and provide clues to the past presence of beavers.

But an abandoned beaver pond can offer its own discoveries. The amount of material amassed to form a dam or a lodge can only be appreciated after the water is drained. The exposed mud can be a great place to find the tracks of other creatures. And old beaver ponds provide great opportunities to find beaver scat. The animals normally defecate in the water, so seeing fresh scat is rare. But once the water has drained out, scats may be left on the sloping inner sides of the dam and the perimeter of the pond. Beaver scat is oblong and can be anywhere from 1/2 to 1 1/4 inches in length. The fibrous content is easy to see in the photo below–a beaver needs to chew through lots of bark and wood to get enough nutrition.

I never get tired of visiting beaver sites, because there’s always something new to discover. Whether it’s the prodigious size of a felled tree, the clever way the animals engineer channels to make transporting logs easier, or a muddy stream margin decorated with the tracks of beavers commuting to and from work, it’s always fascinating. Beavers lead complex lives and show great ingenuity in dealing with their surroundings, and the signs they leave can give us a window into their cleverness and adaptability.

Checking Out Fox Dens

It’s late summer, and fox pups that started life back in late March or early April as small, helpless balls of fluff have grown into sleek coated adolescents. At about five weeks they emerged from the den, and for the next month or so they spent their time near the burrow, developing their strength and coordination through play and mock fighting. They were guarded by parents or females from the previous year’s litter, and at the first sign of danger they dashed to safety below ground. Later they began to accompany their parents on explorations and hunting forays. But even when the kits were quite mobile, the family may have continued to rely on the den as an emergency refuge. I don’t like to disturb fox families until they no longer need that safe haven, so I always wait until late summer or fall before I investigate a fox den.

Fox dens are found in settings ranging from dense cover to open, exposed areas. The den in the photo above was near a house and driveway, but it was well concealed by shrubby cover and wasn’t obvious until I got up close. In the next photo you see the other extreme–a den dug under an old pallet that was located near a highway intersection and lacked any concealing cover. Both of these are red fox dens.

A closer shot of the den in the photo above shows several entrance holes, a throw mound (at the lower right), and tracks in the loose dirt. These photos were taken during the excavation phase, and by mid-spring the den site–and the antics of the pups–were hidden by a screen of grasses and forbs.

Cemeteries are another popular spot for red fox dens. The one in the photo below was behind a grave stone and shaded by a mulberry tree. The black specks you see scattered on the dirt and grass are mulberries.

The mulberry tree was a handy source of food, and fox scat containing mulberry seeds decorated some of the grave markers.

The next photo shows a gray fox den. There wasn’t any concealing cover around the entrance, but getting to it involved a thirty-minute hike and a climb up a steep slope. Gray fox dens are usually farther from human habitation and harder to get to than red fox dens.

There are other medium-sized mammals that use burrows, and distinguishing among them can be tricky. Tracks or direct observation of the residents are the best clues, but failing that we have to rely on other features. One helpful characteristic is the size of the entrance hole: fox dens normally have openings between 6 and 12 inches across, while coyote dens can be twice that. (And like gray fox dens, coyote burrows are not generally found in places with a lot of human activity.) Woodchuck dens have entry hole sizes on the small end of the fox range and can be difficult to separate from fox dens. The most striking difference between the two is the condition of the soil around the entrance. Woodchucks use dens throughout the growing season, and the throw mound, a spreading apron of fresh dirt like the one in the photo below, shows signs of disturbance as long as the resident is active. But unlike fox dens, woodchuck dens show little disturbance of the surrounding soil. These summer lodgings may be abandoned for burrows in more sheltered areas when it’s time for hibernation, and once that happens the soil near the summer den loses its disturbed look.

Fox dens can also have throw mounds (as in the third photo), but they usually have a more trampled look due to the comings and goings of the parents. Once the kits emerge and begin playing, their antics create an area of flattened soil and plant growth much larger than the original disturbance. Active fox dens may also have scat and the bones of small animals nearby. Occasionally, as in the photo below (also in a cemetery), other kinds of toys show what the pups have been playing with.

By the time fall comes the young foxes no longer need an underground refuge, and the area around the den becomes weathered and undisturbed. Unused dens are difficult to assign to an owner and may, in fact, have different residents in the next birthing season. During the winter foxes begin to investigate den sites, and an alert tracker may notice the telltale tracks of a pair of foxes making frequent trips to certain locations. Once the snow is gone favored sites show signs of activity like those shown in the second and third photos.