Are you prepared for another Pennsylvania winter? Our furnace and chimney have been cleaned; the wood shed is full; and warm coats, scarves, mittens and boots are at hand for morning walks.
Wildlife share these same instincts and have been making preparations to spend the winter in a warm place. During periods of cold and snowy weather, most wildlife will remain inactive, staying in their dens until the weather warms.
Recently, my friend, Charlie Fox, mentioned that he has trapped more than 20 mice that invaded his garage. Animals, such as raccoons, have moved into barns and outbuildings, while squirrels often seek out attics. A common complaint received by wildlife conservation officers is that a skunk, or family of skunks, has found a protected place under a porch.
Wildlife will try to find a den to spend the winter. Webster states that a den is a wild animal's lair, the hidden home of a wild animal. Our word "den" comes from the Old English word "denn," meaning "wild animal's lair," which ultimately came from an Indo-European word meaning "flat surface."
Not all animals invade human structures. During the winter months, deer will move near stream bottoms where a stand of evergreen trees grows. Here, the snow will not become as deep and the wind will not blow as strong. These areas are known as deer yards.
Many animals, including squirrels, raccoons, mice and even bear, occasionally move into den trees for the winter. For some animals, a good den tree is necessary to survive the harsh winter months. Hollow trees provide cavities that serve as homes for all sorts of wildlife, from mammals to birds.
After an animal moves into a den tree, the temperature immediately rises. This is due to the animal's body temperature. A drop in the outside temperature will not affect that of the den for at least two hours.
Many birds - most woodpeckers, black-capped chickadees and even horned owls- will nest in the hollow of trees. It takes a long time for trees to form, sometimes more than 100 years before a tree contains a hollow large enough to become a good den tree.
Whether a nest is in an abandoned woodpecker hole or in a natural cavity, a tree den offers better protection from wind, rain and snow. Studies have proven another advantage for animals living in dens is that they use less energy in maintaining their body temperatures.
If a squirrel cannot find a tree cavity for a den, it will build a leaf nest, called a drey. Leaf nests are common in woods that have a shortage of natural den trees. Oak, beech, elm and red maple trees are favored by squirrels for either a den or leaf nest.
Nest building activity mushrooms during June and July when the spring-born squirrels practice building nests, which often are flimsy and seldom last long. Pregnant females about to have their summer litter are busy either building or remodeling nests. Adults often build several temporary nests during the warmer months; however, fall is the most active time for nest construction as both males and females prepare nests for winter.
Leaf nests host a variety of activities throughout the year. During December and January, squirrels are in the midst of their mating period. Although squirrels usually live alone, males and females sometimes share a nest with their mate for a short time during the mating season.
Some animals, such as fox, opossum, porcupine, raccoon, bear and many others, either will dig a hole or use an abandoned woodchuck hole for a den. A fox den also is known as a lair.
I normally think of a den as a bear's winter home; however, many years ago, Deputy Charlie Fox (now Game Commissioner Fox) came upon a freshly dug bear den. At the time, a summer heat wave had us all sweltering, and we realized that the bear had dug the deep hole into the hillside to escape the summer's heat.
Keeping wildlife out of our homes is a yearly task for people who live in the country. By the end of October, wildlife are looking for winter homes, and our homes make ideal dens.
Bower retired after 34 years as a wildlife conservation officer for the state Game Commission. He has published several books about his experiences. Questions and comments may be sent to him at 153 Redington Ave., Troy PA 16947.
