A squirrel’s nest, known as a drey, is a common sight in tree branches, often appearing as a haphazard ball of leaves. While seemingly simple from the outside, this arboreal dwelling serves as a shelter for squirrels, offering protection and warmth. It provides a safe haven for resting, raising young, and escaping predators. The internal construction of a drey is a complex structure, providing insights into the building behaviors of these active rodents.
The Building Blocks of a Squirrel Home
Squirrels meticulously select a variety of natural materials to construct their dreys. The outer framework is woven from twigs, often gnawed from branches while still green, allowing the leaves to remain attached. Inside this twig framework, squirrels pack dried leaves, moss, and strips of bark. They also incorporate softer elements like grass, pine needles, and sometimes materials such as paper or cotton rags if available. These collected items are arranged to form the various layers of the nest’s interior.
Internal Structure and Functional Design
The inside of a squirrel drey reveals a sophisticated, layered design. An outer shell, constructed from interwoven twigs and leaves, provides the primary structural integrity and defense against the elements. Within this robust exterior lies a middle layer, often composed of numerous flattened, dried leaves overlapped like shingles, which creates a thick, insulated barrier. Air pockets trapped within these layers contribute to the nest’s insulating properties, helping to regulate internal temperature.
At the core of the drey is a compact inner chamber, typically six to eight inches in diameter, lined with the softest materials gathered by the squirrel. This chamber may feature shredded bark, fine grasses, moss, lichens, and sometimes even feathers or fur, creating a comfortable and warm resting space. A small entrance hole, often facing towards the tree trunk, allows access while minimizing exposure to the outside environment. This internal arrangement provides effective protection from wind, rain, snow, and potential predators, with the interior temperature potentially being 20 to 30 degrees Celsius warmer than the outside air when occupied.
Seasonal Adaptations and Special Purposes
The internal structure of a squirrel drey can vary based on the season and the needs of the squirrel. Winter dreys are generally larger, more robust, and more insulated, featuring thicker linings of soft materials to provide warmth against colder temperatures. In contrast, summer dreys may be lighter, flatter, and more open, as the need for insulation is reduced during warmer months.
While dreys offer protection, squirrels often prefer natural tree cavities for overwintering due to their insulation and security. If tree cavities are unavailable, squirrels will remain in their dreys, sometimes huddling together to conserve body heat. Nests used for raising young, known as nursery dreys, may be more spacious and feature a softer, finer inner lining to ensure the comfort and safety of the kits. Squirrels maintain multiple dreys within their territory for seasonal living, emergency shelters, temporary resting spots, or as alternative sites if a primary nest is disturbed.