Although Massachusetts is home to 3 types of squirrels - Gray, Red, and Flying, the most common by far is the gray squirrel. They are often seen in a jet black color morph as well, which genetically speaking, is the same species just a different physical attribute. Gray squirrels are diurnal, meaning active in the day, and when it comes to our line of work, most often heard scurrying in your attic in the morning or late afternoon. They spend the majority of days outside foraging as long as weather isn’t too bad.

As with most species, breeding occurs in late winter for young to be born in spring, when food becomes abundant. For gray squirrels specifically, breeding usually takes place in January and February, and young start being born in March and April. There is some variance based on how mild or severe the end of winter is. Typically 3-4 live squirrels are born, and they are hairless with eyes still shut. The eyes stay shut for up to 4 weeks, and fur also begins to grow in then. They nurse from the mother, and will stay in the nest without the ability to move around much for another week or two. They start moving around and becoming really curious at about 5-6 weeks, when they can comfortably move around. The entire time this is going on, the adult female is active in and out of the nest every day caring for them, and the noise can be pretty repetitive. The adult male squirrel that fathered the young does not help in raising them, and may still be in the area but not actively in and out of the nest location. At about 10 weeks of age, the young squirrels (called pups) will be venturing out of the nest and starting to supply food for themselves regularly. Once they’ve fully left the nest, they will often return to visit and sleep but will be spending time trying to establish their own territory and area.

Gray squirrels often breed twice per year, even if the first litter was successful. They don’t need a failed experience to repeat breeding and birthing in the same year, such as birds. In July and August, if food is plentiful, an adult gray squirrel may breed again and prepare to raise another 3-4 pups in August. We see this happen about 1/2 as often as spring mating. The process follows the same schedule.

Gray squirrels are social animals, and seeing them in fairly large numbers in an areas is very common. They don’t nest together during breeding and birthing, but will often group up in winter months and spend time with each other in one structure using the same entry point during those cold spells.