Squirrels are familiar sights in many backyards. These small mammals rely on well-constructed nests for shelter from weather and predators, and to safely raise their young. Understanding their nesting habits offers insight into their behavior.
Understanding Squirrel Nests
Squirrels construct two distinct types of nests: dreys and dens. A drey is a visible, spherical nest found in tree branches. These nests are crafted from interwoven twigs, leaves, and other plant materials, appearing as a messy ball of organic debris.
In contrast, a den is a nest built within a natural cavity or an existing structure. These hidden nests often utilize tree hollows or abandoned woodpecker holes, offering enhanced protection and insulation. Dens are more permanent shelters, providing better defense against harsh weather and potential threats.
Typical Outdoor Nesting Spots
Squirrels frequently build dreys in the forks of tree branches, using the natural stability of converging limbs. These nests are commonly situated high in trees, often 20 feet or more above the ground, which helps protect them from ground-dwelling predators. The dense canopy of deciduous trees like oak, beech, and maple offers both concealment and strong support.
Beyond dreys, squirrels establish dens within natural tree cavities and hollows. These are often pre-existing holes formed by wood rot or created by woodpeckers, which squirrels adapt for their use. Such internal tree shelters offer superior insulation and protection from rain, wind, and snow, making them preferred sites for winter nesting and raising young. Squirrels may also utilize rock crevices.
Indoor Nesting and Shelter
Squirrels sometimes seek shelter inside human-made structures, particularly when outdoor conditions are severe or natural sites are scarce. Attics are a common indoor nesting location due to their warmth, dryness, and seclusion. These elevated spaces mimic the safety of tree canopies, providing an appealing environment for raising litters.
Uncapped chimneys also serve as vertical den sites, offering a dark and protected shaft. Other enclosed spaces like wall voids, garages, and sheds can provide shelter. Squirrels gain entry to these indoor areas by exploiting small gaps, damaged vents, or by gnawing through materials.
Nest Construction and Purpose
Squirrels use a variety of readily available materials to construct their nests. For dreys, they weave together twigs to form a foundational platform. This framework is reinforced with damp leaves and moss, and an outer shell is created by stuffing in more leaves, twigs, and sometimes even bits of paper or trash. The inner cavity of a drey is lined with softer materials such as shredded bark, grass, pine needles, or moss for insulation.
Dens in tree cavities or indoor spaces are lined with similar soft materials like shredded bark, fur, feathers, or even insulation from buildings to create a warm and comfortable interior. Squirrel nests serve multiple purposes: they are primary sites for birthing and raising young, offering a secure nursery. Nests also provide protection from harsh weather conditions and predators. Squirrels may build multiple nests, which can be used as backups in case a primary nest is disturbed or to evade predators.