Jim called to tell me that he had removed the top of a blue bird house and found it full of nesting materials. He began cleaning out the box when an animal popped up from amongst the nesting materials; quickly jumped out and ran up the evergreen tree on which the box was posted. The animal, which startled Jim, was a flying squirrel. Jim then noticed a young squirrel poke its head out of the nest. The young squirrel let out a squeak when Jim picked it up, and the mom came a running down the tree. Jim put everything back the way he found it, and since then, he has not gone near the nest. However, from a distance, he has watched the box and was able to take a picture of mom looking out.
Sometimes the most interesting animals are those living right under our nose; however, their secret lives keep them from being noticed. One such creature is the flying squirrel. Many people have flying squirrels visiting their backyard bird feeders without ever seeing them. This is because the flying squirrel is a nocturnal animal.
Several times in my wildlife career I received calls from lumbermen, telling me that after cutting down a tree, a nest, with flying squirrels, was found in a tree cavity. Once when on foot patrol, I came upon an old barbwire fence, with a flying squirrel hanging from one of the barbs.
The squirrel had glided down from the tree top and hit the barbwire fence, only to get tangled in the wire, and being unable to get loose, the squirrel died.
In Pennsylvania, we have two species of flying squirrels: the northern flying squirrel (Glaucomys sabrinus), which inhabits the northern part of the state, and its smaller cousin, the southern flying squirrel (Glaucomys volans), which lives throughout the state.
Although it is very difficult to tell the difference between the two species, perhaps the location where the animal is found would indicate the species of squirrel. The northern flying squirrel prefers to live in a stand of conifers, while the southern flying squirrel, which is the most common of the two, lives in our hardwood forests, where there is an abundance of nuts. Although squirrels are rodents, they are unlike most
rodents as they neither store food; put on layers of fat nor hibernate.
However, they do den together during the winter months.
The northern flying squirrel is facing hard times and is considered as a threatened species by the Pennsylvania Game Commission and the U.S. Fish and Wildlife Service.
Research has shown that the ranges of the two flying squirrels are beginning to overlap. This spells trouble for the northern species that is already threatened within the state. Their numbers have dwindled because of the European wooly adelgid, which is an insect that has been devouring the state’s hemlock tree stands, the preferred habitat of the northern squirrel. Also, the problem of sharing habitat with the southern species is that a small parasite Strongyloides robustus carried by the southern squirrel can be lethal to the northern squirrel.
According to a study done by the Pennsylvania Game Commission, the parasite poses no threat to the southern flying squirrel; however, it seems to suppress the northerner’s ability to put on weight and also maintain its existing weight.
A more appropriate name for a flying squirrel would be that of gliding squirrel because the flying squirrel does not fly. It glides. On each side of the squirrel, a fur-covered membrane, which runs from just above the paw on the front leg to the ankle on the rear leg, makes it possible for the squirrel to jump from a tree and glide to a lower location.
While in flight, the squirrel uses its tail and legs to change directions. Unless the wind carries the squirrel upward, the rodent can only glide downward Flying squirrels have been known to glide up to 125 feet, usually at a 30 degree angle.
Squirrels eat nuts, seeds, tree blossoms, fungi, fruits, berries, insects and sometimes young birds, bird eggs, small mice and shrews. The northern squirrel feeds heavily on conifer seeds, lichens and truffles (an underground fungi).
Although the flying squirrel’s gliding flight saves energy when moving about, the wing membranes slow them down when running.
Many people that spend time in the woods have never seen a flying squirrel. Jim was fortunate to see one of nature’s most elusive animals.