If you find an infant squirrel, don’t panic. Mother squirrels have more than one nest and can move her infants to the secondary nest if needed. The mother will come back to retrieve her infants when she feels it is safe. If you know mother is around, leave the area so she will feel safe to come back to get her infants. It is best to observe from indoors. If you have not seen the mother after several hours, put the infant in small box and try to get it in the nearest tree or off the ground. Continue to watch from indoors to see if the mother comes back within a few hours. If the mother does not return, there are flies, or the infant is injured, please contact a licensed rehabilitator. If your cat brought home a squirrel in its mouth, please contact the wildlife rehabilitator closest to you.
I found a squirrel flowchart