Eastern Gray Squirrels Swimming
Imagine coming upon a stick floating in a large pond only to discover the “stick” had a head and tail and was making a beeline for the shore. The fact that an Eastern Gray Squirrel (Sciurus carolinensis) had paddled half a mile to get from one shore to the opposite shore of a pond shouldn’t have come as such a surprise, as this rodent has a long history of migratory swimming behavior, but it’s such an incongruous and unexpected event that it made my companion and me initially question our eyesight and then laugh out loud.
Historical reports suggest there have been many massive Eastern Gray Squirrel migrations in the United States, beginning in 1749 in Pennsylvania. Records show the state paid three cents for each squirrel killed; over 640,000 squirrels were turned in for bounty. One migration from Wisconsin in 1842 lasted four weeks and involved a half billion squirrels. Because of the numerous squirrel migrations, John James Audubon was erroneously convinced that the squirrels on the move were a separate species from the Eastern Gray Squirrel and gave them the scientific name Sciurus migratorius. (This proved to be inaccurate.)
During the 1800’s, thousands of squirrels would periodically move en masse across roads, fields and forests, and swim across lakes and rivers (including the Mississippi and Connecticut Rivers) in an effort to disperse. The consensus is that these mass movements were a response to local food conditions. They occurred mostly during the month of September following a year in which there was a large production of food (acorns).
The most recent mass migration of Eastern Gray Squirrels in eastern U.S. occurred in 1968, when a bumper crop of acorns in 1967 was followed with a corresponding bumper crop of young squirrels in 1968. By fall, as the first litter of the year left the nest, there was a severe shortage of food. As a result, massive numbers of acorn-eating squirrels dispersed in search of food.
One Eastern Gray Squirrel swimming across a New Hampshire pond does not a migration make, but it might not be a bad idea to keep an eye out for excessive numbers of paddling squirrels and/or road-killed rodents come September. (Photo by Erin Donahue)
Naturally Curious is supported by donations. If you choose to contribute, you may go to https://naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
Red Squirrels Winter-proofing Nests
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.
Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
Red Squirrels & Sugar Maples
We’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.
Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
Huddling to Keep Warm
Animals which remain active year round in northern New England use different strategies to survive the cold winter temperatures. Lowering metabolism through torpidity (on cold nights black-capped chickadees and other species reduce their body temperature as much as 22 degrees Fahrenheit from their daytime level in a process called regulated hypothermia), shivering, caching food in the fall, puffing out feathers to create insulating pockets of air, excavating tunnels under the snow, seeking protection in cavities – these are just a few of the life-saving techniques used by mammals and birds which neither migrate nor hibernate.
Another strategy which some of these animals use is to huddle together to conserve warmth. Huddling reduces the animal’s surface-area-to-volume ratio, since it turns many small animals into a single big animal. The larger the animal, the smaller the surface-area to volume ratio and the less relative area there is to lose heat.
Bluebirds and flying squirrels are two animals which huddle to keep warm. Eastern bluebirds may huddle together in a tree cavity or hollow log in groups of up to ten. Flying squirrels often huddle together in large communal nests, sometimes with populations numbering over two dozen squirrels, in an effort to keep warm. If this is not sufficient, the squirrels will enter a state of torpor until temperatures return to normal. (Thanks to Susan Parmenter for photo op.)
Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
Red Squirrel’s Winter Coat
There is a marked seasonal difference in the Red Squirrel’s appearance due to its two annual molts (spring and fall). In the winter, a broad rusty-red band extends along its back, from its ears to the tip of its tail. The Red Squirrel’s thicker winter coat also includes ear tufts, which no other species of squirrel in the Northeast possesses. Come spring, when the squirrel sheds again, it loses its ear tufts and its new coat is closer to an olive-green color than red.
Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
Discerning Eastern Gray Squirrels
In 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.
Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.
Red Squirrel Gardens in the Woods
Red and Gray Squirrels remain active year round, and thus, need to have access to food throughout the year. In order for this to happen, seeds and nuts must be stored in the warmer months for consumption during the winter and early spring, when food is much harder to find. While Gray Squirrels tend to bury nuts and seeds individually for this purpose, Red Squirrels often cache numerous seeds (mostly conifers and maples) in one spot, dispersing these caches throughout the woods. During the winter Red Squirrels use their memory (and sometimes their sense of smell) to locate these buried treasures. Inevitably some are overlooked and in many of these cases, the seeds germinate. Finding little patches of multiple seedlings, such as this miniature stand of young Sugar Maples, is a good indication that at least one Red Squirrel overwintered in the vicinity.
New Children’s Book by Mary Holland
Do you know a 3 – 8 year old who loves animals and would enjoy getting close-up views of the antics of a red fox kit during the first summer of his life? My second children’s book, Ferdinand Fox’s First Summer, has just been published by Sylvan Dell in both hardback and paperback. I have been lucky enough to have had the opportunity to observe and photograph young red foxes as they interact with each other and with their parents. This book consists of a selection of these photographs, accompanied by text and an educational component at the end of the book. Look for Ferdinand Fox’s First Summer in your local bookstore. If they don’t carry it, you would be doing me a huge favor by asking them to. Thank you so much. My next children’s book is on Beavers and will be coming out in the spring of 2014. (I am still looking for a publisher for Naturally Curious Kids!)
A Great Christmas Present!
If you’re looking for a present for someone that will be used year round, year after year, Naturally Curious may just fit the bill. A relative, a friend, your child’s school teacher – it’s the gift that keeps on giving to both young and old!
One reader wrote, “This is a unique book as far as I know. I have several naturalists’ books covering Vermont and the Northeast, and have seen nothing of this breadth, covered to this depth. So much interesting information about birds, amphibians, mammals, insects, plants. This would be useful to those in the mid-Atlantic, New York, and even wider geographic regions. The author gives a month-by-month look at what’s going on in the natural world, and so much of the information would simply be moved forward or back a month in other regions, but would still be relevant because of the wide overlap of species. Very readable. Couldn’t put it down. I consider myself pretty knowledgeable about the natural world, but there was much that was new to me in this book. I would have loved to have this to use as a text when I was teaching. Suitable for a wide range of ages.”
In a recent email to me a parent wrote, “Naturally Curious is our five year old’s unqualified f-a-v-o-r-I-t-e book. He spends hours regularly returning to it to study it’s vivid pictures and have us read to him about all the different creatures. It is a ‘must have’ for any family with children living in New England…or for anyone that simply shares a love of the outdoors.”
I am a firm believer in fostering a love of nature in young children – the younger the better — but I admit that when I wrote Naturally Curious, I was writing it with adults in mind. It delights me no end to know that children don’t even need a grown-up middleman to enjoy it!
Flying Squirrels Visiting Bird Feeders
Are you finding that the amount of seed in your bird feeders drops precipitously after dark? Those of us in black bear country are advised to bring feeders in at night so as not to attract bears, but occasionally several hours of darkness have passed before I remember to do so. When that happens, the feeders inevitably need filling. What stealthy critter is visiting once the sun goes down? Very possibly, flying squirrels are the culprits. These nocturnal rodents can glide as far as 295 feet from tree to tree, or tree to ground. They stretch their legs out and direct their glide by controlling the position of the flap of skin (patagium) that extends from the outside of the wrist on the front leg to the ankle of the hind leg on both sides of their body. Their broad, flattened tail acts as a parachute, rudder, stabilizer and brake during the glide. Feeders are rarely far enough from a tree to necessitate a glide – a short leap does the trick. If you feed birds, try shining a light on your feeders after the sun goes down. You may very well be treated to the sight of several flying squirrels helping themselves to your sunflower seeds and suet.
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.
Black Walnut
Even though a late spring frost may have reduced this year’s crop of Black Walnuts (Juglans nigra), and even though the few that made it haven’t started falling on the ground yet, squirrels have already located and started consuming this nut’s fatty meat. Inside the green husk is the actual nut, and if you look closely at the edges of the chewed hole as well as the inner surface of the nut, you will see tiny incisor marks, most likely left by red squirrels. This particular rodent typically chews a hole on both sides of the nut, so that it can gain access to both halves of the meat.
Naturally Curious with Mary Holland 
What Other Naturally Curious People Are Saying