Squirrels are a common sight, and their agile movements through trees often lead people to wonder about their homes. These creatures build nests high within tree canopies, which are essential for their survival and various life stages. These structures provide squirrels with shelter and a safe haven from external threats.
The Two Main Types of Tree Nests
Squirrels use two main types of nests in trees: dreys and tree cavities. A drey is a spherical nest constructed from leaves, twigs, and other plant materials. These are often visible as ball-shaped structures, roughly the size of a football, tucked within tree branches or close to the trunk for stability. Dreys are a common sight, especially in deciduous trees during winter when leaves have fallen.
Tree cavities, also known as dens, are natural hollows or abandoned holes found within tree trunks or large branches. These cavities often originate from natural decay or are created by other animals, such as woodpeckers. Squirrels adapt these spaces by lining them with soft materials. Tree cavities are preferred over dreys, particularly in colder months, as they offer superior protection from harsh weather and predators.
Why Squirrels Need Nests
Squirrel nests serve multiple purposes for their well-being and reproduction. They provide shelter, protecting squirrels from diverse weather conditions, including rain, snow, strong winds, and extreme temperatures. During colder periods, nests offer insulation, helping squirrels conserve body heat, as they remain active year-round.
Nests also offer protection from predators, allowing squirrels to evade threats by retreating into these secure spaces. A significant function is to provide a safe location for female squirrels to give birth and raise their young, known as kits. Nests can also serve as resting spots throughout the day and, to a lesser extent, for temporary food storage.
How and Where Nests Are Built
Squirrels construct their arboreal homes using readily available natural materials. For dreys, they gather twigs, leaves, moss, and grass, weaving these components into a sturdy, spherical structure. The outer layer consists of interwoven twigs and leaves that provide structural support and insulation against wind and water. The interior is lined with softer materials like shredded bark, moss, grass, feathers, or pine needles to create a warm and comfortable inner chamber, often 6 to 8 inches in diameter.
The drey construction process begins with a base of loosely woven twigs, followed by packing damp leaves and moss to reinforce the platform. A spherical frame is then woven, forming the outer shell, with additional materials stuffed in to build up the structure. For tree cavity dens, squirrels line existing natural holes or abandoned woodpecker nests with similar soft materials to enhance insulation and comfort. Nests are placed high in trees, typically at least 20 to 30 feet (about 6 to 9 meters) above the ground, often in the crotch of branches or close to the main trunk for stability and concealment.