© squirrelrehabilitation.com, 2011 Natural History Nests Below are pictures of the lining of two birthing nests.  Each was received from tree trimmers, and each came complete with babies (two and three).  They are approximately ten inches in diameter and four to five inches in height.  They are made of very finely shredded (hair thin) fibers--wood primarily but with leaves also included.  They are quite soft inside (not the abrasive sticks and dried leaves many people think when they see the outside structure of the nests).   The first picture has a softball inside to give an idea of the size.  Notice that the mother can close the nest when she goes out to forage, leaving the babies snuggled safely inside and surrounded by insulation to keep them warm. Click on pictures to increase size. Second nest pictured below was slightly damaged.