Squirrels exhibit intricate behaviors, with their nesting habits being particularly fascinating. These small mammals construct shelters that serve multiple purposes throughout their lives. Understanding when and why squirrels build these structures provides insight into their adaptability and survival strategies.
Seasonal Nest Building
Squirrels engage in significant nest construction during two primary periods, aligning with their breeding cycles. The first phase occurs from late winter to early spring (February-March) as they prepare for initial litters. Female squirrels create warm, secure environments for their young, often refurbishing existing nests or building new ones. A second wave of activity emerges in late summer to early fall (July-September) for a second litter.
New nest construction is most intense in the fall. Squirrels diligently gather materials and reinforce nests to withstand colder months, ensuring insulation. While these periods mark peak activity, squirrels may build or maintain nests opportunistically year-round. This ongoing maintenance ensures accessible shelter for protection or resting.
Different Kinds of Nests
Squirrels construct two primary types of nests: dreys and cavity nests. Dreys are visible structures, appearing as spherical masses of twigs and leaves, found high in tree forks or branches at least 20 feet above ground. Often mistaken for bird nests, dreys are usually larger and more disheveled. A simple drey can be completed in a single day, while reinforced versions may take a week or two.
Cavity nests are located within natural tree hollows or abandoned woodpecker holes. These provide superior protection from weather and predators due to their enclosed nature. Squirrels prefer cavity nests for raising young and for winter shelter due to enhanced security and insulation. Many squirrels maintain multiple nests, sometimes two or three, as backup shelters or temporary resting places.
Reasons for Nest Construction
Nests are crucial for squirrel survival, fulfilling several roles. A primary reason for construction is to provide a safe location for raising young. Maternity nests offer warmth and security, allowing vulnerable offspring to grow protected from external threats.
Nests also protect from predators, offering a hidden refuge. This concealment helps squirrels avoid detection while resting or sleeping. Nests provide shelter from harsh environmental conditions, including cold, heat, rain, and strong winds. The insulated structure helps squirrels conserve body heat in winter and escape heat in summer, making them important for year-round survival.
What Nests Are Made Of
Squirrels gather various materials from their surroundings to construct nests. The outer framework of a drey typically consists of woven twigs, providing the basic spherical shape. This structure is reinforced by packing in damp leaves and moss, which adds stability and insulation. The interior of the nest is carefully lined with softer, finer materials to create a comfortable and insulated living space.
Common lining materials include shredded bark, grass, dried leaves, pine needles, and feathers. Squirrels use their mouths and front paws to collect and process these items, often tearing them into smaller pieces for a denser, more insulating layer. In urban or suburban environments, squirrels can be opportunistic, incorporating human-made items such as insulation, fabric scraps, paper, or plastic into their nests, especially when natural materials are scarce.