Squirrels are a common sight across many landscapes, from dense forests to urban parks. These small mammals rely on carefully constructed nests for shelter and to support their life cycle, serving as central hubs for their survival and reproduction.
Peak Nesting Seasons
Squirrels are most active in nest-building during two primary periods, aligning with their breeding cycles. The first major nesting season occurs from late winter to early spring, from February to April. During this time, female squirrels prepare for their first litters, constructing secure nests to ensure the safety and warmth of their young.
The second wave of nesting takes place from late summer to early fall, between August and September. This period corresponds with the second breeding season, requiring new or reinforced nests for subsequent litters. Squirrels also intensify building efforts during autumn to prepare for colder months, gathering materials to insulate their homes. Some opportunistic building or repairs can occur throughout the year as needed.
Factors Driving Nest Construction
Several factors prompt squirrels to build or maintain nests. Reproduction is a primary driver; females require a safe, warm, and concealed location to give birth and raise offspring. Nests offer a protected nursery where young can develop before venturing outside.
Nests also provide protection from the elements, shielding squirrels from cold, rain, wind, and heat. They serve as a refuge from predators, offering an elevated and camouflaged hiding spot. Squirrels may also use nests for temporary food storage, especially in preparation for winter when food sources are scarce. The availability of materials, such as twigs, leaves, moss, and shredded bark, influences when and where squirrels build, as they are resourceful in their collection.
Types of Squirrel Nests
Squirrels construct two main types of nests, each suited for different purposes and offering varying levels of protection. The most commonly observed type is the drey, a spherical structure built high in tree branches. These nests are composed of interwoven twigs, dry leaves, and other plant materials, often lined with softer elements like moss, grass, or shredded bark for insulation and comfort. Dreys are used for general shelter, resting, and raising young. Summer dreys may be lighter in construction than winter versions.
The second type is a tree cavity nest, also known as a den. These nests are found within natural tree hollows or abandoned woodpecker holes, which squirrels may modify. Tree cavity nests offer superior insulation and protection from harsh weather and predators, making them a preferred choice, especially during colder months or for birthing. Squirrels often maintain multiple nests of both types within their territory, switching between them to evade predators, escape parasites, or for convenience while foraging.