Squirrels are a familiar sight in many outdoor spaces, often seen scurrying up trees or burying nuts. Among their most visible signs are the large, spherical nests nestled high in tree branches. These seemingly haphazard collections of leaves and twigs often spark curiosity, leading many to wonder how such structures can possibly withstand the elements. The question of whether these arboreal homes are truly waterproof is a common one.
Understanding Squirrel Nests
Squirrel nests, known as dreys, are not entirely waterproof like a manufactured container. Instead, their design emphasizes weather resistance and water repellency, effectively shedding precipitation. While some moisture might penetrate the outermost layers, the core of the nest typically remains dry. Dreys are distinct from “den nests,” which are built inside tree cavities or burrows and offer superior protection from the elements. While den nests are often preferred for severe weather and raising young, dreys are the more commonly observed squirrel homes.
Building a Weather-Resistant Home
Squirrels construct their dreys using a multi-layered approach for weather resistance. The outer layer consists of a tightly interwoven framework of twigs and branches, bent and woven into a sturdy, spherical or football-like shape. This dense outer shell acts as a primary barrier, deflecting wind and shedding most rainfall away from the nest’s core. The placement of these materials, often in the secure fork of a tree branch, contributes to the overall stability and resilience of the structure.
Beneath this robust outer layer is an inner lining made from softer, insulating materials. Squirrels gather items such as dried leaves, moss, shredded bark, grasses, and even fur or feathers to create a plush interior. This inner chamber is designed to trap air. The overall dome shape and tight weaving of the drey further assist in channeling water downwards and away, while an entrance often positioned towards the tree trunk offers additional shelter from direct rain and wind.
Staying Safe and Dry Inside
The layered construction of a drey provides insulation, which is crucial for a squirrel’s survival across seasons. The trapped air within the thick walls helps to maintain a stable internal temperature, keeping the occupants warm during colder months and offering some respite from summer heat. Studies have indicated that the interior of an occupied drey can be considerably warmer than the ambient air temperature.
Even if the outermost layers of the drey become saturated during heavy downpours, the inner chamber often remains relatively dry. Squirrels frequently maintain multiple dreys and occasionally relocate if a primary nest becomes too damp or compromised. This adaptive behavior, combined with the nest’s insulating properties, allows squirrels to effectively utilize these weather-resistant structures for shelter, resting, and raising their young.