We have lots of gray squirrels here too. They are a pest at times. They do dig in the yard and since there are lots of nut trees around this time of year they are very busy. A few years ago they got under our roof vents and chewed threw the screen and got into our attic. What a mess they made. To solve that problem we took old freezer baskets and put them over the top of the vents. Now just a few days ago one not so smart, nosey squirrel fell down our chimney and landed on the pipe for our wood stove. After a lot of scratching the stupid thing slipped down the rest of the way to the wood stove. So you think you have a problem. There is no way to get the critter out with out having it running around the house, so we are waiting for the poor thing to die. Now will have to put something over the chimney top so this won't happen again. My grandkids couldn't figure out why the squirrel couldn't climb back out, after all Santa does!!!