Grey squirrels are common, adaptable rodents found across various landscapes, from woodlands to urban areas. Their flexible nesting strategies allow them to thrive in diverse environments. Understanding where these agile creatures build their homes reveals insights into their behavior and how they interact with their surroundings.
Tree Nests: Dreys and Cavities
Grey squirrels primarily construct two types of nests in trees: dreys and natural tree cavities. A drey is a spherical nest, often appearing as a messy ball of leaves and twigs. Squirrels weave together small branches, leaves, moss, and other plant materials to form a sturdy, football-sized structure, typically located high in tree forks or close to the trunk, often at least six meters (20 feet) from the ground. The exterior is often a loosely woven framework of twigs, while the interior is lined with softer materials like moss, feathers, grass, and shredded bark for insulation.
Squirrels also utilize existing hollows in tree trunks or abandoned woodpecker holes as nesting sites, referred to as tree cavities or dens. These natural shelters offer enhanced protection from predators and superior insulation against harsh weather conditions. Females often prefer these more secure locations for giving birth, as the survival rate for young born in tree cavities tends to be higher than in dreys. Squirrels line these cavities with soft bedding materials, such as leaves, to create a comfortable and protected environment.
Nesting in Human Structures
Grey squirrels frequently utilize human-made structures for nesting, particularly in suburban and urban settings. Common locations include attics, sheds, garages, and even chimneys. They can also gain entry into walls, eaves, and soffits, finding concealed spaces within buildings.
Squirrels are drawn to these structures for several reasons. Human dwellings offer warmth and consistent shelter from predators and environmental elements, making them appealing alternatives to outdoor nests. Attics, for example, are often quiet, dark, and provide insulating materials like fiberglass that squirrels can use for nest construction. Sheds and garages also provide secure environments for raising young.
Seasonal Nesting Choices
Grey squirrels exhibit dynamic nesting behaviors throughout the year, often maintaining multiple nests and selecting different types based on seasonal needs. They do not hibernate, remaining active year-round.
During warmer months, dreys are frequently used for sleeping and raising litters. As winter approaches, squirrels shift towards more insulated options to conserve body heat and protect against cold temperatures. This typically involves moving into natural tree cavities or seeking refuge within human structures like attics, which offer superior warmth and protection from freezing conditions. Females typically have two litters annually, one in early spring and another in late summer, often choosing the most secure nest for their young.