Squirrels are a common sight in many backyards and parks, often seen scampering up trees or burying nuts. Their homes, often observed high in tree branches, provide shelter from various elements and a safe space for their daily activities. Understanding where and how these adaptable animals build their shelters offers insight into their survival strategies.
The Primary Nest: Dreys
The most frequently observed squirrel nest is called a drey. This structure appears as a messy, spherical ball of leaves and twigs, often positioned in the forks of tall trees or close to the main trunk. Dreys can measure approximately 30 centimeters (12 inches) or more in diameter, with some eastern gray squirrel dreys reaching up to two feet wide. Squirrels construct the outer layer from interwoven branches and green twigs, which, as they dry, help secure the structure. The interior is lined with softer materials, including shredded bark, moss, grass, pine needles, and sometimes even feathers or human-made debris like plastic or paper.
Dreys provide refuge from weather and predators, and are also used for raising young, though females typically nest alone during pregnancy. While appearing somewhat fragile, dreys are surprisingly secure and can be waterproof. Squirrels often build more than one drey within their territory, using these additional nests as reserves, escape routes, or to avoid parasites.
Other Squirrel Shelters
Beyond dreys, squirrels also utilize tree cavities, commonly referred to as dens. These dens are natural hollows found within tree trunks or large branches, or sometimes abandoned holes created by woodpeckers. Squirrels adapt existing cavities, occasionally widening an entrance hole if necessary. Like dreys, dens are lined with soft materials such as leaves, moss, and shredded bark for insulation and comfort.
Dens offer squirrels more robust protection from harsh weather, particularly during colder winter months, due to their enclosed nature. They are often the preferred location for raising winter litters, as the insulated environment helps the young survive. Squirrels may also share dens with other squirrels during cold spells to conserve body heat. Having both dreys and dens allows squirrels flexibility, as they may move between different shelters depending on the season or immediate needs.