Gray Squirrel Dreys

With most deciduous trees having lost their leaves, squirrel nests, or dreys, are more noticeable. Red Squirrels, Eastern Gray Squirrels and Flying Squirrels all build dreys. Those of the Red Squirrel are round, grassy balls, 8” – 10” in diameter. In contrast, Gray Squirrel nests are usually larger and made of sticks and leaves. Flying Squirrel dreys are so high that they are rarely observed.

The dreys most commonly seen are made by Gray Squirrels. Usually 30 or more feet high, these shelters are typically built near the main trunk of the tree, in a crotch where several small branches meet, or on a strong, thick limb. Construction takes place in the summer or early fall, before trees have formed the abcission layers that cause leaves to separate and fall from branches. Therefore, the leaves on a drey’s branches tend to remain for quite some time, forming an effective water-shedding outer layer.

Branches are loosely woven into a foot-wide hollow sphere. The drey is lined with insulating grass, moss, leaves, and shredded bark. Usually there is one entrance/exit hole, facing the trunk (so as to keep rain out). Often squirrels build two dreys, giving themselves another shelter option should one nest be disturbed by a predator or overrun with parasites.

A drey is usually inhabited by one squirrel, but two are known to occupy a single drey in order to keep warm in the winter. Gray Squirrels give birth in late winter and again in the summer. A more protective tree cavity usually serves as a nursery in the winter, and the drey in summer. The average drey is only used for a year or two before it is abandoned.