Squirrels, familiar inhabitants of many landscapes, are active during the day and require a safe place to rest at night. Their choice of shelter is not random; these clever rodents construct or find dwellings that offer protection and comfort. Understanding where squirrels find refuge provides insight into their remarkable adaptability and survival strategies.
Primary Resting Places
Squirrels primarily utilize two main types of arboreal shelters: dreys and tree cavities. A drey is a nest constructed by the squirrel itself, typically appearing as a spherical ball of leaves and twigs high in the branches of a tree. These structures are usually found in the forks of tall trees, often 20 feet or more above the ground, providing stability and elevation.
Drey construction begins with a base of woven twigs, onto which damp leaves and moss are packed to reinforce the structure. The outer shell, often 10 to 30 inches in diameter, is made from sticks and leaves, while the inner cavity, approximately six to eight inches across, is lined with softer materials such as shredded bark, grass, moss, pine needles, or even fur. This design often includes one or two entrance holes, usually positioned towards the tree trunk to shield against rain and provide an escape route.
Tree cavities, also known as dens, offer an alternative dwelling for squirrels. These natural hollows can form through processes like tree decay or by the abandonment of holes created by woodpeckers. Squirrels will adapt these existing cavities by lining them with moss and leaves to create a comfortable and insulated space. Ground squirrels, in contrast, typically create tunnel systems and burrows underground for their sleeping quarters.
The Rationale Behind Their Choices
The selection of a sleeping location is driven by several benefits that contribute to a squirrel’s survival. Both dreys and tree cavities offer protection from predators, such as owls and other climbing animals, by providing elevated and often concealed positions. A drey positioned high in a tree offers a vantage point, while a tree cavity provides a more enclosed and secure hideaway.
These shelters also provide insulation against weather extremes, shielding squirrels from wind, rain, and snow. The multi-layered construction of a drey, with its dense outer shell and soft inner lining, helps to regulate temperature, keeping the occupants warm in colder conditions and cooler during warmer periods. Tree cavities offer protection from the elements due to their enclosed nature, making them particularly effective against harsh weather.
Adapting to Seasons and Family Needs
Squirrel sleeping habits and dwelling preferences often shift with the changing seasons and family requirements. While dreys are commonly used during warmer months, tree squirrels often seek out more robust shelters like tree cavities as winter approaches. These natural hollows offer better waterproofing and windproofing, which is particularly beneficial during the coldest periods.
Tree squirrels do not hibernate; instead, they remain active year-round, relying on their well-insulated dens to conserve energy during cold spells. During severe winter weather, multiple squirrels may huddle together within a drey or cavity to share body heat. Dreys, while sometimes adapted for winter by adding more layers, are generally less effective than tree cavities for extreme cold.
For mothers raising their young, dreys and tree cavities serve as safe nurseries. Squirrels typically have two litters a year, one in late winter or early spring and another in late summer. The chosen nest must be spacious enough to accommodate the litter, and mothers may even move their kits between multiple nests if one becomes compromised or more suitable shelter is found. The security and insulation of these structures are important for the survival of newborns.