Squirrels are skilled architects, constructing various types of nests that provide essential shelter and a safe haven. Their nest-building habits are fundamental to their survival and ability to thrive in diverse environments.
The Arboreal Drey
The most recognized squirrel nest is the “drey,” an arboreal structure typically found high within trees. A drey appears as a spherical or oblong mass, often compared to the size of a football, ranging from approximately 30 to 60 centimeters in diameter. Squirrels meticulously construct these nests using a variety of natural materials collected from their surroundings. The outer framework is built from intertwined twigs and branches.
Inside this robust exterior, squirrels pack layers of softer materials to create insulation and comfort. These inner linings include moss, dried leaves, grass, shredded bark, pine needles, and sometimes feathers or fur. Dreys are usually situated in the strong forks of tree branches or close to the main trunk, typically at least six meters (about 20 feet) above the ground, providing stability and protection. These structures become readily visible in tree canopies once leaves fall in autumn and winter.
Beyond the Drey: Other Squirrel Homes
While dreys are common, squirrels also frequently utilize other types of dwellings, particularly tree cavities. These natural hollows within tree trunks or large branches are often referred to as “dens,” offering a robust and protected living space. Squirrels may take over existing hollows formed by decay or natural processes, or even abandoned woodpecker holes, sometimes gnawing at the entrance to widen it.
Tree cavity dens generally provide superior insulation and protection from harsh weather conditions, such as rain, wind, and extreme temperatures, compared to dreys. They also offer enhanced security from predators. Although dens are often preferred for their durability and warmth, they are less readily available than suitable sites for drey construction. Some ground squirrel species, distinct from their tree-dwelling relatives, create intricate underground burrows for shelter and raising young.
Why Squirrels Build Nests
Squirrels construct or adapt nests for several important purposes fundamental to their survival and reproductive success. Nests provide refuge from adverse weather conditions, including rain, snow, strong winds, and both extreme heat and cold. The thick walls and insulated linings of dreys, especially winter dreys, trap air, helping to maintain a warmer internal temperature.
Nests also offer protection from predators, as they are typically located high in trees, away from ground-based threats. Crucially, nests serve as safe nurseries for raising young, often called kits. Female squirrels rely on these secure structures to give birth and provide a protected environment for their litters. Squirrels often maintain multiple nests throughout their home range, using them as backup options if a primary nest is disturbed or for temporary resting spots.