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Red Squirrel

Eastern Gray And American Red Squirrel Food Caching Strategies




Red Squirrel Belly Flop

Congratulations to Mary Pratt, the first reader to correctly identify the impression a Red Squirrel left in the snow.  Red Squirrels are fiercely territorial, and will chase each other furiously in order to defend their territory and their food caches. The photographer, Susan Bull Riley, witnessed this behavior as she watched two Red Squirrels racing after each other in the crown of a maple tree.  Suddenly one of them fell to the ground, where sleet and wet snow cushioned its fall and recorded the belly flop landing.  No time was lost in the resumption of the chase!

There were many “Flying Squirrel” responses, which makes great sense as they are approximately the same size as a Red Squirrel (just an inch or two shorter in length) and are gliding from tree to tree or from tree to the ground.  My assumption is that a Flying Squirrel’s landing impression might show some of the patagium, or membrane, that stretches from a squirrel’s wrists to its ankles, due to the fact that it is extended as the squirrel glides. (Any firsthand Flying Squirrel landing-in-snow impression observations welcome.) Thanks to all who submitted an answer to this Mystery Photo.  Many were very amusing!


Some Ways Mammals Stay Warm In Winter

When temperatures drop significantly, mammals that stay active in the winter have a variety of ways to keep warm, one of which is to have layers of insulation to prevent their body heat from escaping.  Often there is a layer of fat under the skin. In addition to providing a source of energy, fat doesn’t transfer heat as well as other tissues such as muscle or skin, and thus helps to insulate an animal’s body. The next layer consists of a short, dense coat of underfur which is filled with air pockets that provide insulation.  Lastly there frequently is a third layer of oily, water-repellent guard hairs which excel at keeping out water. They are often transparent and hollow, providing extra thermal insulation.

Voles, mice, shrews and red squirrels use elaborate tunnels systems under the snow to escape cold temperatures and strong winds.  Flying Squirrels huddle together in groups to keep warm. Shivering is a warming technique used by many mammals, including humans.  And some active animals, like the pictured Gray Squirrel, simply find a sheltered spot in the sun, close their eyes, and soak up the warmth!  (Thanks to Jody Crosby for photo op.)



Red Elderberry Attracts Wildlife Year Round




Red Squirrels Caching Food For Winter

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Both carnivores and herbivores cache, or store, food for later consumption. Black-capped Chickadees tuck seeds into bark crevices. Bobcats may cover their kills with leaves, grass, snow and even hair from their prey’s carcass. Grey Squirrels bury their nuts individually, while Red Squirrels often hide green cones in a pile of cone scales (middens) that accumulate at the site where the squirrels have previously eaten seeds, keeping the young cones moist so that they will retain the seeds within them.

Red Squirrels sometimes go one step further than most animals that cache food — they frequently preserve their food by drying it before storing it.  You’ll recognize this when you see it – an apple or mushroom stuck in the crotch of two branches. Sometimes the dried food is collected and cached near their winter quarters, but often it remains lodged in tree branches until eaten.  The pictured mushroom, which was hung out to dry, was reduced almost to mush by the torrential rains we’ve had lately. Eventually it will dry out and remain edible into the winter.


Gray Squirrel Dreys

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With most deciduous trees having lost their leaves, squirrel nests, or dreys, are more noticeable. Red Squirrels, Eastern Gray Squirrels and Flying Squirrels all build dreys. Those of the Red Squirrel are round, grassy balls, 8” – 10” in diameter. In contrast, Gray Squirrel nests are usually larger and made of sticks and leaves. Flying Squirrel dreys are so high that they are rarely observed.

The dreys most commonly seen are made by Gray Squirrels. Usually 30 or more feet high, these shelters are typically built near the main trunk of the tree, in a crotch where several small branches meet, or on a strong, thick limb. Construction takes place in the summer or early fall, before trees have formed the abcission layers that cause leaves to separate and fall from branches. Therefore, the leaves on a drey’s branches tend to remain for quite some time, forming an effective water-shedding outer layer.

Branches are loosely woven into a foot-wide hollow sphere. The drey is lined with insulating grass, moss, leaves, and shredded bark. Usually there is one entrance/exit hole, facing the trunk (so as to keep rain out). Often squirrels build two dreys, giving themselves another shelter option should one nest be disturbed by a predator or overrun with parasites.

A drey is usually inhabited by one squirrel, but two are known to occupy a single drey in order to keep warm in the winter. Gray Squirrels give birth in late winter and again in the summer. A more protective tree cavity usually serves as a nursery in the winter, and the drey in summer. The average drey is only used for a year or two before it is abandoned.

Bumper Cone Crop Year

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There is no denying that this year’s cone crop is a bumper crop. Just look up at the tops of conifers or down on the ground beneath them and you will see a plethora of cones. This may be the best overall cone crop in five years, and the best spruce cone crop in more than a decade in the Northeast.

Conifers produce cone crops erratically; some years are bountiful, and others are minimal. Part of the reason for this may be that in a year with a bumper crop (mast), predators can’t possibly consume all of the seeds produced, and thus the opportunity for conifers to have their seeds dispersed and germinate is markedly improved. In addition, erratic production may have partially evolved as a strategy to combat insect damage. An unpredictable cycle makes it much more difficult for insects to become a pest.

As to why some years are so productive, weather conditions are certainly influential. Often times people look at the most recent summer’s weather as a forecaster of the coming fall’s hard mast crop (nuts, cones). Although most conifer cones develop in six to eight months, not all do. Most conifers in the family Pinaceae take this amount of time, but cedar cones take a year to mature, and most spruce and pine cones mature in two to three years. Thus, the cone crop we are having this year may in part be a reflection on this year’s weather, but, depending on the species, it could have been influenced by last summer’s weather conditions or even the summer before last.

Regardless of why some years are lean and some plentiful, when we have a bumper cone crop such as this fall’s, the impact is felt far and wide by wildlife. Red squirrels, voles, waxwings, chickadees, nuthatches, grosbeaks, crossbills and siskins reap the benefits. Their resulting reproduction rates soar, and the ripple effect continues to be felt throughout the food chain.

In some circumstances, the ramifications of a bumper crop are evident before the crop even matures. It appears that red squirrels can predict when there is going to be a huge spruce cone year and produce a second litter to take advantage of the large food supply when it matures. It may be that when the squirrels eat the buds of a spruce tree the summer before cones develop (spruce cones take two years to mature — cone buds are produced in the first year and cones develop and mature in the second year) they can discern which buds are going to produce cones and which are destined to produce branches. An abundance of cone buds may be the clue that triggers their extended reproductive activity. (Photo: Red Spruce cones)


Squirrels Digging For False Truffles

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Such creative and informed answers to yesterday’s Mystery Photo, and many that were right on the mark!  To set the stage, several 2” to 4”-deep holes riddled the ground under a stand of Eastern Hemlocks. Something had obviously been digging for something, but who and what? Close inspection of the holes revealed two things. The animal that had dug the holes had run into some thick hemlock roots, and with a clean 45° angle cut, had snipped them in order to have access to the soil beneath them. Secondly, some of the holes had pea- to marble-size, spherical tan objects that resembled puffballs both lying at the bottom and wedged into the sides of the holes.

Only because I had read Paul Rezendes’s Tracking & the Art of Seeing years ago did I recognize these holes and spherical structures within as the work of an animal looking for false truffles (a genus of fungi) to eat. By putting the various clues together – a hemlock stand, 3” to 6”-wide holes, clean incisor-snipped roots, and a few remnant truffles – the mystery at to what was being sought was solved.

As to who had done the digging, white-tailed deer, squirrels and porcupines all fancy false truffles. Both porcupines and squirrels have incisors that would make a clean cut through the roots. If porcupines had been digging here, there would likely be scat and/or quills lying about, which there were not. Thus, most likely it was a squirrel that had smelled, unearthed and eaten the false truffles.

Rezendes found that the truffles he discovered had dried spores inside them, and assumed that this made them undesirable to the animal that unearthed them and therefore they were not eaten. The spores of the truffles I found were not dried out, so I have no idea why they weren’t eaten, but I’m very glad they weren’t, as their presence allowed me to solve this mystery and see this phenomenon which I’ve been looking for for decades.

It may interest some to know that false truffles and Eastern Hemlocks have a symbiotic relationship. The fungi are attached to hemlock roots, so the minerals and water they absorb are available to the hemlocks. The hemlocks provide the fungi with sugars that they (hemlocks) produce through photosynthesis. Squirrels (and porcupines and white-tailed deer) and eastern hemlocks have a similar mutually beneficial relationship in that hemlocks provide the truffle-eaters with food, and the squirrels, porcupines and white-tailed deer disperse the spores of the truffles they’ve eaten. (Caution: Do not eat false truffles – they are considered toxic to humans.)



Red Squirrel Sign



Red Squirrels Eating Snow

1-11-17-red-squirrel-eating-snow-049a2569Red Squirrels have very efficient kidneys, so most of their water requirements are supplied in fruit, buds, fungi and other food that they eat. They are said to rarely drink free-standing water or eat snow, even when it is available. However, both the scat and the chewing marks in the snow surrounding the scat in yesterday’s Mystery Photo were made by a Red Squirrel.


Porcupines Foraging For Acorns

10-12-16-porcupine-20161011_4950If you live near a stand of Red Oak trees, your chances of seeing a Porcupine this fall are greater than average. At the end of August, when the apple supply has dwindled, Porcupines move on to important new food sources – acorns and beechnuts. While American Beech trees in central Vermont have not produced a bumper crop of beechnuts this year, Red Oaks are experiencing a very heavy mast crop. These acorns provide sustenance for many animals – Black Bears, Red and Gray Squirrels, Eastern Chipmunks and other small rodents, White-tailed Deer and Wild Turkeys, to name a few.

Porcupines are typically one of the first acorn consumers, as they are able to climb oaks and eat the acorns before they drop and are accessible to many of the other animals that are limited to foraging on the ground. If you see the tips of branches nipped off with acorn caps (but no acorns) still attached lying under an oak tree, it’s likely that a Porcupine has been dining in the tree and discarding branches after scooping out and eating the acorns.If the tree is large, the Porcupine may reside in the canopy for several days. (Thanks to Emma for photo op.)


Red Squirrels Dining on Black Walnuts




Red Squirrels Winter-proofing Nests

11-18-15 red squirrel2  032Red Squirrels are active year round and have nests that they can retreat to at any time of the year. These nests are used for shelter and rest, for over-wintering and as brood chambers. Red Squirrels build them in a variety of spots (tree cavities, old woodpecker holes, middens, rock piles, rotting logs, tree canopies) with a variety of material (twigs, branches, leaves, shredded grape bark, etc.).

Regardless of where they build their nest or what they build it with, Red Squirrels line it with fine, relatively soft material, such as grasses, bark fibers, feathers and fur. If a Red Squirrel happens upon potential nest-lining material, including an old dog towel hung out to dry, it will readily chew it into shreds and carry them back to its nest.


Red Squirrels Making Middens

10-15 red squirrel midden 209Red squirrels bury food for winter consumption both individually as well as in caches or “middens.” These food supply piles may be in a hollow tree, in an underground den or in a hollow at the base of a tree. Middens consist of intact cones, cut when they are green with their seeds still enclosed, as well as debris (woody bracts, or scales, etc.) from the cones that accumulates from the squirrel’s eating the seeds. If a midden is located underneath a favorite feeding site, not only is the midden large (up to four feet tall), the moist, decomposing pile of scales provides an ideal place for stored cones to be kept fresh and viable, as the moisture keeps them from drying and opening. Other foods, including nuts, hawthorn and sumac fruit, are also stored in this way. (Note entrance hole at base of midden.)


Red Squirrels & Sugar Maples

2-20-15 red squirrel2 IMG_7851We’re approaching what is often a very stressful time of year for many animals, including red squirrels. In the fall they feed on all kinds of conifer seeds, mushrooms, insects, nuts and the many fruits and berries that are available. They also have caches of cones, which they turn to once there is a scarcity of food elsewhere.

Once these caches are used up, usually by late winter or early spring, red squirrels turn to sugar maples for nutrients. Their timing is perfect, for this is when sap is starting to be drawn up from the roots of trees. Red squirrels are known to harvest this sap by making single bites into the tree with their incisors. These bites go deep enough to tap into the tree’s xylem tissue, which is where the sap is flowing. The puncture causes the sap to flow out of the tree, but the squirrel delays its gratification. It leaves and returns later to lick up the sugary residue that remains on the branch after most of the water has evaporated from the sap.

Not only do red squirrels help themselves to sugar maple sap, but they have developed a taste for the buds, and later in the spring, the flowers, of both red and sugar maples. Red squirrels are not the only culprits – gray squirrels and flying squirrels also make short work of buds and flowers from these trees.


Red Squirrels Tunneling

2-10-15  red squirrel snow tunnel IMG_0579Although most of their food is stored above ground, red squirrels will also bury some in underground tunnels. The holes (2” to 4” diameter) leading to these underground caches are somewhat larger than those of chipmunks and often have a pile of cone bracts (midden) right outside or nearby. In winter, red squirrels also make snow tunnels (above the ground), which allow them to run from one food source to another in relative safety. Gray squirrels occasionally will tunnel, but not to the extent red squirrels do.


The Effects of An Icy Crust on Wildlife





Red Squirrel’s Winter Coat



Discerning Eastern Gray Squirrels

1-3-14 gray squirrel2 029In the fall, Eastern Gray Squirrels bury individual acorns from Red and White Oaks to sustain themselves through the winter. The acorns of Red Oaks have delayed germination – they can be stored up to six months before they start germinating. The acorns of White Oaks, however, have no such dormancy, and begin to germinate in the fall, soon after they fall from the tree. Once acorns sprout, they are less nutritious, as the seed tissue converts to the indigestible lignins that form the root. Gray Squirrels, as a means of “long-term cache management,” selectively remove the embryos from White Oak acorns (but not from Red Oak acorns) before burying them. Germination is prevented, and the storage viability of the White Oak acorns is extended by six months, equaling that of the Red Oak acorns.


Interpreting a Kill Site

12-18-13 hawk kill IMG_4136When there’s snow on the ground and you come upon a site where a predator successfully caught prey, there are usually signs that will help you determine who the main players were. In the above scene, remnants of red squirrel fur confirm the identity of the prey. If you look at the top of the image, you can make out a faint wing impression. Although not in this case, both wings of an avian predator often touch the surface of the snow, allowing you to measure the wingspread, and this information can help to eliminate some species of raptors. Birds of prey often defecate at a kill site. In the lower left corner of the photograph, as well as to the left and right of the packed area where the squirrel was eaten, you can see white (uric acid) bird droppings. Given that it is a hawk or an owl, knowledge about their respective evacuation habits will allow you to narrow down the possibilities even further. Owls tend to let their droppings do just that – drop, leaving small plops on the ground. Hawks, on the other hand, tend to forcefully eject their droppings some distance away. The long, thin streaks at this site were definitely propelled outwards, making it likely that the predator was a hawk. Familiarity with the hawks that overwinter in your area can help pinpoint which species it could be.


Shagbark Hickory Nuts Ripening



Red Squirrel Gardens in the Woods


A Great Christmas Present!





Red Squirrel Sign

If you find a mushroom hanging in an unlikely spot, such as from tree branches or tucked into the bark of a tree where it didn’t grow, it’s likely that you have happened upon the work of a red squirrel (Tamiasciurus hudsonicus).  Red squirrels are known for their habit of snipping mushrooms and hanging them from branches and rough bark in order to dry them before collecting them and caching them for dining on later in the winter.   Unlike beavers, which share their stored cache of winter food with family members, red squirrels keep their cached fungi all to themselves.