Master 2138, Tape 1 MS tree with den hole. One young Gray Squirrel (Sciurus carolinensis) pops his head out of the den hole. Another squirrel is on the back of the tree; he climbs around to the den hole. Both squirrels retreat into the den. A third squirrel climbs down the tree trunk and into the den. The squirrels have been scared by a crow's call.