You have to catch them and kill them. They can really make a friggin mess and cause a lot of damage. DON'T WAIT! You are about to have an entire family up there...I would go with the Bill Murray cattyshack approach to getting rid of them.
Don't let them live, kill them and all their babies.
I had them in VA, and heard them in the attic. They made a hole in the side of the house and got in there and made a big mess which lead to other problems. DO you have a tree right next to the house?...If so remove it.
These guys come back like a bad dream. You have to kill them.

