Love ‘em or hate ‘em, everyone knows squirrels. “Squirrels,” however, is a generic term. I use it here to refer to game species — gray, fox and red squirrels. These are the three species of tree squirrels that most eastern state wildlife agencies recognize as game species.
To confuse the issue just a bit, some states also list “black” squirrels in their hunting regulations. And though melanistic (black) squirrels occur widely, they are not a distinct species. Black squirrels are a genetic form or “morph” of gray and fox squirrels. (Melanism is an overdose of dark pigments (melanins) which are under genetic control.)
Telling them apart
Distinguishing among the three species of tree squirrels is relatively easy. Beyond the obvious color differences, red squirrels are small (about eight ounces, twice the size of chipmunks) and have a distinct white eye ring.
Gray squirrels weigh about a pound, and the tips of the hairs on the tail are white, giving the tail a frosty appearance.
Fox squirrels weigh about two pounds, and the tips of its tail hairs are orange-brown. Its belly is also often orangish to reddish brown. Fox squirrels are often erroneously called “red” squirrels, and this adds to identification confusion.
The best way to distinguish among tree squirrels is by size. Red squirrels are about twice as big as chipmunks; gray squirrels are twice the size of reds; and fox squirrels are twice the size of grays. A little time spent watching all three species makes these size differences obvious.
Black morphs create confusion. Here again size is the best characteristic, because both gray and fox squirrels occur in black forms.
Black morphs can be surprisingly common where hunting is prohibited. City parks and college campuses can be reservoirs for melanistic morphs of both gray and fox squirrels. Nature seems to frown on individuals that stand out — perhaps they’re too easy for predators to spot. In any case, populations of black squirrels of either species tend to be local and isolated
Ecologically, tree squirrels share similar habitats and have similar reproductive habits. Gray and fox squirrels inhabit parks and deciduous woodlands in the eastern U.S.
Gray squirrels are most commonly seen in wooded backyards and city park setting. In nature they prefer mature oak-hickory forests. Fox squirrels prefer more open wooded areas. A good general rule is that where oaks thrive, both gray and fox squirrels will be nearby.
Fox squirrels typically require a larger home range than gray squirrels. The more open habitat fox squirrels prefer has fewer nut-bearing trees per acre than the denser forests gray squirrels prefer. Fewer trees means fox squirrels must roam more widely in search of food.
Both gray and fox squirrels begin to compete for mates in late December. Chasing females is an important part of the ritual, and it can go on for weeks. Mating occurs some time in January.
The breeding biology of gray and fox squirrels is similar. Gestation is surprisingly long for such small rodents. Litters of two to five kits (average three) are born in a tree cavity lined with leaves about 45 days after mating. Birthing peaks in mid-March. Newborn squirrels measure about two inches in length and weigh about one-half ounce.
Development of the young is slow. Baby squirrels open their eyes at four to five weeks and wean at about eight weeks. It’s usually May before young squirrels can be seen scampering in treetops.
If food is abundant and females are healthy, a second litter follows in July or early August. In years following a poor nut crop or a severe winter, females forego the summer litter.
Red squirrels are the smallest tree squirrels in North America. What they lack in size, they compensate for with attitude. They are vocal and aggressive. Where reds overlap with grays and foxes, red squirrels are often behaviorally dominant.
Though mature coniferous forests of white pine and hemlock are the red squirrel’s preferred habitat, they also occur in mixed woods and sometimes even pure deciduous stands.
Red squirrels mating behavior follows the pattern for grays and foxes, but it does not begin until February, and only southern populations typically have a second litter.