Biology Reference
In-Depth Information
Another amusing trait is the red squirrels' penchant for closely pursuing each other. A common sight
in the woods is to see one red squirrel racing after another at top speed across the ground, then chasing it
around and around a tree trunk in a sharp upward spiral. At some point the whole affair is reversed, and
the two spiral down the tree and speed away out of sight. All the while, the two squirrels will maintain
the same distance of a foot or two from each other, so perfectly synchronized that their capers resemble
the operation of some mechanized toy.
Living accommodations for the two species differ greatly. Though both like tree dens, the grays are
also great summer nest builders. The presence of gray squirrels is often revealed by these great, rounded
bunches of leaves and twigs, sometimes several to a tree. Such nests, called
dreys,
are usually placed
away from the trunk, where the juncture of two or more branches makes a convenient platform. Dreys
are constructed so as to shed water. They're hollow, with an entrance hole, and, like nests in tree cavit-
ies, are lined with whatever soft materials are available.
Grays tend to utilize several tree cavities—sometimes as many as seven— if they're available, but
usually they have both dens and dreys. Once the young have been born, the mother will frequently
move them from one den or nest to another.
This may be partly a defensive strategy, making it more difficult for predators to dine on baby
squirrel. Biologists also speculate, however, that it may be a way of avoiding the major flea infesta-
tions—sometimes thousands in a den—that regularly plague squirrels. Indeed, one squirrel biologist
who sported a full beard was finally forced to shave it off because so many squirrel fleas hopped into
it!
Red squirrels also den in tree cavities; when these are lacking, they'll build dreys, though in much
smaller numbers than the grays. However, the reds are just as apt to den in a burrow in the ground,
often dug between the roots of a tree or under their food cache. When they do build nests, these are
placed close to the trunk of a tree and are much smaller and less conspicuous than the nests of the grays.
Usually the red's nest is constructed of twigs, or twigs mixed with shredded bark, with far fewer leaves
than the gray's leafy bower.
Red squirrels remain highly active most of the time during the winter, though they may sometimes
hole up for a day or two in exceptionally stormy or bitter weather. They are always solitary in the winter,
and may den in a tree cavity, in a burrow, or simply in tunnels in the snow.
Reds also like to expropriate birdhouses for a den. While cleaning out our bluebird houses one
spring, I failed to pay sufficient attention to the fact that the house was full of various soft plant materi-
als. As I dug down into the mass, I was startled to feel movement and hear an angry squabbling sound.
At the first glimpse of red fur, I realized that I had wrecked the happy winter home of a red squirrel,
which was now decidedly indignant!
Gray squirrels also remain active throughout the winter, although they may be semi-dormant for a
couple of days during unusually inclement weather. Unlike the solitary reds, grays also den commun-
ally. These dens are shared by males and juveniles, which are very sociable and may groom each other.
Breeding females, on the other hand, are cantankerous and den by themselves. Gray squirrels in the
