A drey — or dray — is a nest of a tree squirrel or a flying squirrel. Dreys are usually built of twigs, dry leaves, and grass, and typically assembled in the forks of a tall tree. They are sometimes referred to as “drey nests” to distinguish them from squirrel “cavity nests” (also termed “dens”). In temperate regions, dreys become much more visible in the autumn, when leaf-fall reveals new nests built the previous summer or in early fall.