Category: scat

River Otters: Living in Two Worlds

I’m fascinated by river otters. Well, I guess I’m fascinated by all animals, but otters hold a special appeal. We humans can relate easily to their playfulness and sociability. The otter pictured below was photographed at the Lindsay-Parsons Biodiversity Preserve in Tompkins County, New York. This expanse of ponds, meadows, wetlands, and forests is one of many protected areas managed by the Finger Lakes Land Trust. It’s open to the public and is a great place to watch otters. And even if an otter doesn’t show itself while you’re there, you’ll probably find evidence of its presence in the form of tracks, scat, or resting areas.

Photo by Scott Levine, Finger Lakes Land Trust

Scat (sometimes called spraint) is probably the most obvious sign left by otters. Their diet of fish, crayfish, crabs, freshwater and saltwater mussels, and even small mammals and birds brings with it indigestible parts which end up in fecal material. In the center and upper left of the photo below you see formed scat containing crayfish shell fragments held together by finer material. The roughly tubular shape of these deposits indicates that they are relatively recent. Under the influence of rain and weathering otter scat readily disintegrates into scatterings of the more visible parts, like the fish scales at the lower right.

Scat is an important means of communication among otters and is usually placed in significant locations, such as on trails between bodies of water, near dens, and at resting areas. Popular locations may accumulate scat of varying ages, and the collections become especially large when several otters are using the area. In the photo below large piles of scat lie in the lower middle part of the frame, and smaller deposits can be seen both uphill and downhill. The entire area has a trampled look, and in the upper part of the photo, slightly to the left of center, there’s a slight hollow that is relatively bare of debris. It looks like both a comfortable resting spot and a good lookout over the river below.

Otters are fastidious about keeping their fur in good condition, and in addition to grooming, the animals do a lot of rolling. This dry wash technique removes both grime and water, helping to maintain the insulating qualities of the coat. Rolling spots may be in conifer duff, grass, soil, sand, or even in snow. The animal that made the roll in the photo below came out of the water from the ice hole at the left. Around the edges of the roll the snow was pushed outward by the otter’s feet, and in the center it was flattened as the otter writhed on its back. There are some nice tail marks at the upper right. After it rolled the otter went right back into the water, leaving a few tracks and a body slide on the left side of the photo. There’s a great video here that shows the playful energy of a rolling otter.

Sliding is another favorite otter pastime. While the animals will occasionally slide downhill on grass or mud, sliding reaches its apogee in snow. On good snow an otter can slide down hills, on level terrain, and even up slight inclines, using its feet only when needed to keep the joyride going. And joyride isn’t an exaggeration. Otters sometimes make repeated slides, turning around and going back time after time to enjoy another go.

And then there are tracks. Otter tracks are similar to those of other members of the Mustelid family, with five toes arranged asymmetrically on both front and back feet. The animal that made the tracks in the photo below was moving from lower left to upper right. The first print at the lower left is the left front, the next is the left rear, then comes the right front and finally the right rear. This pattern of front-hind-front-hind, and the space separating the first group of four from the next group, are typical of the lope, the otter’s preferred gait. Another cogent detail is the relative sizes of the prints. The rear tracks (the second and fourth in each group) are larger than the front tracks, a feature that distinguishes otter tracks from the similar-sized tracks of the fisher. The otter’s hind feet are webbed, and the toes can spread widely to make optimal use of the webbing when swimming. There’s a hint of webbing in the right rear print in the first group shown below, but webbing doesn’t always show in tracks. And as you can see from the photo, tail marks may not be present. In fact they’re rare unless the animal is moving in deep snow.

When otters are in the area they usually leave plenty of evidence, but you may miss it unless you look in the right places. These include silty or sandy shorelines, grassy or forested stream banks, ice-covered ponds and streams, beaver dams or artificial dikes, peninsulas, and trails or elevations between bodies of water. As you observe these places you’ll get a feel for convenient travel routes, good rolling spots, and preferred resting areas. Bluffs of banks with easy access from the water and padded with soft forest duff are always good places to check and often have tracks, scat, rolls, or other evidence of otter activity. The places otters choose are often the places I’d pick for a pleasant lunch stop. Looking down on a river from such a spot I can imagine an otter emerging from the water, loping up the bank, and making a quick check of the situation. Perhaps it examines scat left by another member of its family group and adds some of its own to the collection. Or maybe it enjoys a short rest and a good roll before returning to the water for more foraging.

The aquatic part of an otter’s life is mostly hidden from us, but as soon as it leaves the water an otter leaves evidence of its life on land. Reading those messages can give us glimpses into the lives of these truly remarkable animals.

Getting to Know Porcupines

I’ve been thinking about porcupines. There are porcupines in central New York where I live, but they’re not common, so in that region (unlike in the Adirondacks) I don’t often encounter their tracks. But this spring we had some late April snowfalls, and on two different occasions I was surprised and excited to find porcupine trails. In the photo below (direction of travel from right to left) you can see the left front and left rear tracks. The hind track (on the left) shows the flattened sole area of the foot nicely, with the marks of the claws to its left. The smaller front print lies to the right but isn’t as clear because the thin snow fractured in the sole area and three of the four claw marks were covered by the hind print.

Those meager April snowfalls weren’t ideal for recording clear tracks, so I’m including a more revealing photo of porcupine tracks that I took a few years ago in the Adirondacks. There was a light skiff of snow on a dark, icy base, and the soles and claws can be seen clearly. Again, the tracks are left front and hind, and the direction of travel is toward the upper left. In the rear print (on the right) the sole is larger but the claws are shorter than in the front print (on the left). If you look carefully at the front track you can see the faint imprints of the front toes (which usually don’t show up at all) just behind the dark holes made by the claws. And those streaks that run toward the upper left from the front claw impressions are drag marks made by the claws as they came forward when the foot was lifted.

So what if there’s no snow? Following trails may not be an option, but porcupines leave plenty of other evidence of their presence. Their winter diet includes the inner bark of trees, both conifers and hardwoods, and the buds and leaves of conifers. Scenes like the one pictured below (on yellow birch) show how efficient a porcupine can be at removing the cambium tissues of living trees. And this kind of evidence lasts long after the actual feeding was done. Small debarked patches high in hardwoods (but not conifers) could also be due to squirrels, which may turn to bark feeding when other food is scarce. However, the amount of exposed wood in the photo below is more than a squirrel would be able to achieve.

To get at tree buds or leaves a porcupine climbs high into a tree (where the most vigorous branches are), bites off twigs, eats the buds or leaves, and then drops the twigs. The photo below shows a scattering of nip twigs which accumulated on the ground as a porky fed in the hemlock tree above. When porcupines feed on the swelling buds of sugar maples in early spring, or on acorns in late summer, they harvest and discard the twigs in a similar manner.

But twigs and branches can fall with no help from porcupines, so how do we know whether a porky was the culprit? The first clue is the relatively even sizes of nip twigs (mostly 1 1/2 to 2 1/2 feet), compared with the wide range of sizes when wind or ice damage is the cause. Another clue is the appearance of the separation site. Randomly broken branches and twigs have ragged, irregular ends. The photo below shows the clean, angled cut found on a red oak twig that was nipped by a porcupine.

To get to feeding spots high in the canopy a porcupine must climb trees, and on trees with light bark, like the aspen in the photo below, climbing marks are very visible. Aspens are sought out by porcupines in spring when the leaves are young and easily digested, and preferred trees are often visited several years in succession. Bears also climb trees to feast on young leaves, nuts, and fruits, but the spacing between porcupine claw marks, between 1/4 and 3/4 of an inch, is much closer than the spacing in climbing marks left by bears.

Porcupine dens are another unmistakable sign. Unlike many other animals, porcupines defecate in their sleeping areas, and when scat piles up they simply plow through it or push it out of the way. The trunk of the sugar maple in the photo below had a hollow space which served as a porcupine den, and the waterfall of scat which fell down from it is evidence of an extended period of occupancy. Porcupine scats are cylindrical to kidney-shaped, and they can also be found among the nip twigs dropped from favored feeding trees.

In spite of their prickly defense, porcupines are preyed upon by most medium-sized carnivores. I found the coyote scat in the next photo last winter, earlier but in the same general area where I found the nip twigs and the tracks in the April snow. The coyote could have been responsible for the porky’s death, but it’s also possible that the initial killer was a fisher, and that the coyote scavenged the carcass later. The quantity of quill fragments is surprising and makes me wonder whether any quills entered the coyote’s body.

By now porcupines have left the mature forests and moved to more mixed habitats where they can find the growing herbaceous shoots and leaves, cattails and other wetland plants, roots, tubers, and fruits that make up their spring and summer diet. There are lots of other animals which consume the same plants, so unless you actually see a porcupine having a meal it’s hard to recognize the signs of summer feeding. But if you’re alert you may find long-lasting evidence of their cold weather activities.

Logs

Living creatures see the world in terms of significant objects. We humans are no exception–for us significant features would be such things as chairs, doorways, computers, streets, buildings, picnic tables, traffic lights….you get the idea. For wild animals rocks, thickets, streams, cliffs, and trees come to mind. And then there are logs–items that we usually ignore unless we’re looking for a place to sit. Downed logs are important to many animals in many different ways, and the evidence is often plain to see.

A chipmunk sat on the log in the photo above to eat a red oak acorn. In order to get at the edible meat, the animal tore narrow strips and small chunks from the outer covering. Logs serve as feeding platforms for many small rodents, including red and gray squirrels, and the leftovers often reveal who the diner was. When squirrels feed on red oak acorns, the shell fragments left behind tend to be larger than those discarded by chipmunks.

The log above was used by a red squirrel feeding on red pine cones. As the squirrel fed it dropped the cone scales and cores on the ground in front of the log to create a large midden. Red pines are self-pruning trees and don’t offer many branch perches, so although red squirrels prefer the safety of branch perches, they sometimes need to use more earth-bound objects. Logs, stumps, and rocks can offer a good view of the surroundings and allow the animal to detect danger.

And how do we know it was a red squirrel? Although gray squirrels do sometimes eat conifer seeds, they don’t store them the way red squirrels do, and they never feed on enough conifer cones to create middens the size of the one in the photo.

Tracks on logs tell us that they can also serve as travel routes. Of course we need snow to see this kind of evidence–the light snowfalls of early winter and early spring often show the prints of animals that walked on logs. The coyote that made the tracks in the photo above found the log to be a convenient route through an area obstructed by branches and undergrowth. Walking on logs may also be quieter since leaves and debris can be noisy, even under a layer of snow. Another advantage of walking on logs is a better view. The greater elevation helps prey animals to detect danger, and predators to detect prey. I’ve found many different tracks on logs–the list includes squirrels, white-footed mice, chipmunks, raccoons, bobcats, bears, red and gray foxes, coyotes, fishers, minks, and weasels.

Logs offer these same advantages when there’s no snow, so we can be sure that animals also walk on logs in warmer weather. Without snow their tracks are difficult to detect, but we may still find evidence of their passing. A long-tailed weasel left the scat shown in the photo above on a mossy log. The scat was not quite 1/4 inch in diameter and contained hairs from a small mammal.

The logs in the photo at the head of this article are ones I visit regularly, and they often accumulate the scat of several different kinds of animals. This suggests that they have some special importance, but I’m not sure exactly why. The log in the foreground bridges a low, rocky gully, but the more distant one lies on more level ground. Both logs are large, but there are other logs nearby that are as big or bigger and don’t accumulate scat. Whatever the reason, we can be sure that each species that travels those logs takes note of the messages left by other creatures.

In addition to serving as perches, travel routes, and bulletin boards, logs may be a source of food. This log was torn open by a black bear in search of the grubs that were living and feeding in the rotting wood. Bears are not the only creatures that find food in logs–skunks, raccoons, and woodpeckers also open logs in search of edible morsels. But the size of the fragments and the distance to which they were thrown could only have be the work of an animal as powerful as a bear.

Have you heard a grouse drumming this spring? At this time of year ruffed grouse are looking for mates. The males seek out large logs, and once they find a log that offers a stable and well elevated surface they send out a kind of drumming sound with their wings. The low sound travels long distances, and the elevation of the log gives it even more range. Females are drawn to the sound, and if they’re impressed they will mate with the male. In the photo above I’m perched on a grouse drumming log, taking a photo with my old SLR camera. In front of me on the log you can see several grouse scats.

Whether they’re dinner tables, highways, message boards, pantries, stages, or even just obstacles, logs are significant objects for inhabitants of the natural environment. The evidence they present can reveal unseen dramas in the lives of animals. So before you sit on that log, take a look at it. You might be rewarded with a message that opens a window into the life of a wild creature.

Ruffed Grouse Snow Beds

When the snow gets deep and temperatures go down, ruffed grouse have a wonderful way of staying warm overnight. They can’t climb down into woodchuck burrows the way rabbits do, or follow narrow openings down to warmer depths like weasels. And they don’t curl up with their tails over their heads like foxes. But they can fly, and that allows for a unique strategy. In mid-flight, a grouse tucks its wings close to its body and dives into the snow. Once submerged all it takes is a few wiggles to shape a perfectly formed and well insulated snow cave.

I found the grouse bed pictured below back in November after an unusually early snowstorm. The place where the bird plunged into the snow is on the left, and the exit side of the bed is at the lower right. The trail the bird made as it walked away extends toward the top of the frame.

Here’s the same grouse bed from another angle–the entry is now at the top of the frame and the exit is at the bottom. The cavity where the bird spent the night is located under the undisturbed snow between the two holes. If you could peer down into the lower hole you would see a chamber roughly the shape of the grouse’s body.

If you can’t picture how it all happened you’re probably not alone. One of the keys to interpreting nature’s messages is to go back in time to the beginning of the incident and work your way through to the end.

Consider what happens when you toss a ball into soft, fluffy snow. The ball disappears and leaves nothing but a small depression where it went in. It’s only when you grope around trying to find the ball that more of the snow gets disturbed. A similar situation occurs with a grouse’s snow bed. Once the bird disappears under the snow, the only sign on the surface is a depression where it went in. The grouse can’t be seen, and there’s smooth, undisturbed snow everywhere except for a hollow of tossed snow. It’s not until the next morning, when the bird wakes up and begins to wriggle forward and upward, that the snow around it is disturbed and at least one other hole in the snow appears.

In the photo above, you can see some dark material in the lower hole. A close-up shows that the dark material in the cavity is scat. Grouse typically defecate before they begin to work their way out of the their snow cave.

If the snow isn’t deep enough–or soft enough–for a plunge, grouse rest in surface beds like the one shown in the photo below. On the right side of the photo you can see a hollowed out, grouse-body-sized depression. The usual scat pile sits in the bottom of the bed, and the tracks made by the bird as it walked away can be seen heading toward the left. The scat in the surface bed (and also in the snow cave in the preceding photos) is dry and fibrous, the type of scat produced from the grouse’s normal winter diet of buds, twigs, and catkins. But in the photo below there’s another kind of scat, lying roughly in the center. This wetter, softer scat is called caecal scat, and it’s produced when a grouse eats higher quality food, such as the cambium layer of woody plants. More nutritious food goes through an additional digestive process in specialized intestinal pouches called caeca.

I marvel at the adaptations that ruffed grouse–and other creatures–have for coping with the challenges of winter. And I love the way such behaviors become more real when when I can see and understand the actual evidence. It’s worth the effort to parse out the story and see what birds and animals really do to survive.