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.)
An obvious sign of Red Squirrels, especially noticeable if snow is still on the ground, is the remains of their feeding activity. In winter and early spring, when snow may make finding food on the forest floor difficult, Red Squirrels show a preference for conifer buds. Rather than scurrying up a tree and eating the buds, they first prune the branch tip from the tree, eat the buds and then discard the tip onto the ground. Spruces, hemlocks and firs are some of their main sources of buds. If the squirrel feeds for a significant amount of time, the forest floor under the conifer it is feeding in can become littered with branch tips. Nip twigs scattered on the ground beneath hemlocks are also a sign of Porcupine feeding, but the tips they drop are much longer than the 2- to 4-inch tips discarded by Red Squirrels. (Photo: Balsam Fir branch tips; Inset – lateral buds of Balsam Fir branch tip eaten by Red Squirrel)
Red 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.
If 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.)
The method in which a nut has been opened depends on both the species of nut as well as the species of animal that opened it. To complicate things further, it can be difficult to ascertain who opened a nut as a given species, such as the Red Squirrel, often has more than one way of opening a nut. However, a given squirrel usually chooses one way to open a nut and consistently uses that method, so that if you come upon a pile, or midden, of nuts eaten by a Red Squirrel, the nuts will most likely all have been opened in the same way.
The beveled edges on the hole in the pictured Black Walnut, the fact that it was opened from both sides (leaving the dividing rib between the two sides intact), and the central location of the holes are indications that a Red Squirrel dined on the nutmeat. The chewing of open, jagged holes on either side of a nut is a Red Squirrel’s most common method of opening a nut. Gray Squirrels tend to remove the entire side of a walnut, as opposed to chewing a hole in it.
Red 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 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.)