The Eastern Grey Squirrel (Sciurus carolinensis) is a familiar sight across North America, often seen foraging on the ground. While the grey squirrel spends a great deal of time digging, it does not construct extensive, permanent subterranean burrows for shelter. This tree-dwelling species utilizes the soil for a specific, temporary purpose, while reserving its true habitation for elevated locations. The act of digging is a seasonal behavior driven by survival, not an architectural need for a dwelling.
The Purpose of Digging
The primary reason Eastern Grey Squirrels dig is a survival strategy known as scatter hoarding. This involves burying individual food items, such as nuts, seeds, and acorns, in numerous temporary caches throughout their territory. The holes created are highly specific, typically only large enough to fit a single nut and are shallow, often no more than one to two inches deep.
These shallow excavations are purely functional, designed to hide provisions from competitors for later retrieval during times of scarcity. The squirrel uses its forepaws to quickly dig a small depression, places the item, and then covers it by tamping down the soil with its snout. The squirrel does not rely on memory to find these hundreds of caches, but instead uses its highly developed sense of smell to locate the buried food, even through snow. Digging activity is also observed when the squirrel re-digs a cache to check on or move a stored item.
Primary Shelter: Arboreal Habitats
Since the Eastern Grey Squirrel does not burrow for shelter, its true homes are found high above the ground in arboreal habitats. The species relies on two main types of elevated structures to protect itself from predators and the elements. The most common is the drey, a spherical nest constructed in the forks or branches of trees.
Dreys are built from an interwoven mass of twigs, leaves, moss, and other plant materials, making them well-insulated and approximately 12 to 18 inches in diameter. These nests are frequently used for resting, temporary shelter during warmer months, or as a secondary home.
For more permanent and secure housing, particularly during the coldest parts of winter or when raising young, the grey squirrel prefers natural tree cavities. These cavities are typically hollowed-out sections of a tree trunk or large branch, sometimes utilizing abandoned woodpecker holes. A tree cavity provides superior insulation and protection compared to a drey, functioning as a warm, secure den.
Distinguishing Squirrel Holes from Other Wildlife Activity
The small, numerous holes left by Eastern Grey Squirrels are easily distinguished from the permanent burrows of other digging mammals. A squirrel cache hole is characterized by its small, coin-like diameter, usually one to two inches across, and its extreme shallowness. Crucially, a squirrel hole lacks a significant mound of excavated dirt next to the opening because the soil is quickly scraped back over the buried nut.
In contrast, the true burrow of a groundhog (woodchuck) will be much larger, often eight to twelve inches in diameter, and will have a substantial, visible mound of dirt piled at the entrance. Chipmunk holes are also small, around silver-dollar size, but their entrances are exceptionally neat, lacking the scattered soil of a squirrel’s hurried caching effort.
Therefore, if a small hole is noticed that is clean and lacks displaced soil, it is a sign of a squirrel’s brief food-caching activity. This is distinctly different from the entrance to a complex, permanent underground dwelling.