Squirrels utilize a variety of locations for shelter and raising their young, remaining active year-round. The specific type of nest or shelter they select is dictated by the season, local climate, and resource availability. This structure is known as a drey, which describes any squirrel nest. The primary purpose of a drey is to provide a safe, insulated space for sleeping, escaping predators, and birthing litters, which typically occur twice a year.
Constructed Nests in Trees
The most recognizable squirrel shelter is the constructed nest in a tree, most often seen during warmer months. This structure is built from scratch, primarily using a dense mixture of twigs, green leaves, and shredded bark interwoven into a spherical shape. This creates a sturdy, hollow ball that is wind and waterproof.
The exterior is a rough, interwoven shell, while the interior is lined with soft materials such as moss, grass, pine needles, or fur for insulation. Dreys are usually positioned high in the tree canopy, often between 20 and 40 feet above the ground. They are placed in a strong fork of branches or tight against the main trunk for support, which also helps shield the single entrance hole from rain and wind.
Nests Inside Natural Tree Cavities
Squirrels frequently seek out pre-existing holes or hollows in trees, known as cavity nests or dens, as an alternative to building a drey. These natural formations, such as former woodpecker holes or hollowed-out sections of a trunk, offer superior protection and insulation. The wooden walls provide a ready-made, windproof structure often preferred for surviving the coldest winter months.
Unlike a constructed drey, the squirrel does not build the outer shell; instead, it focuses on lining the interior. They furnish the existing hole with insulating materials, like dried leaves and shredded bark, creating a warm chamber. This type of nest is a more permanent, secure shelter than a leaf drey, offering better defense against predators and harsh weather.
Nests Inside Residential Structures
When natural tree cavities are scarce, squirrels in urban and suburban areas often adapt by nesting inside human dwellings. Attics are a prime target because they mimic the elevated, protected space of a tree hollow, offering warmth and seclusion. Squirrels access these spaces by exploiting architectural vulnerabilities, requiring only a gap of about 1.5 inches to enter a structure.
Common entry points include poorly sealed roof edges, damaged fascia boards, and gaps in soffits (the material covering the underside of a roof overhang). They will also gnaw through damaged roof vents, ridge vents, and uncapped chimneys, viewing these openings as suitable den entrances. Once inside, they build a nest in the attic rafters, wall voids, or crawl spaces, often using readily available materials like insulation, shredded paper, or fabric.
How to Identify a Squirrel Nest
A constructed squirrel drey appears as a bulky ball of leaves and twigs, typically ranging from 12 to 30 inches in diameter. A key feature differentiating a drey from a bird’s nest is its construction: it is a fully enclosed sphere with one or two small entry holes, unlike the open-cup structure of most bird nests. Bird nests, such as those made by crows or hawks, tend to be flatter, platform-like, and made primarily of thicker sticks.
Squirrels often maintain multiple dreys, using some as temporary resting places and others as dedicated breeding nests. A nest used for raising young, known as a natal drey, is more robust and meticulously constructed than a simple sleeping drey. If the structure is active, you may also find evidence of chewed pinecones or nut fragments on the ground directly beneath the tree.