I have a mama squirrel that has lived in the greenhouse in winter for several seasons. At least I think it is the same mama, it could be her daughter or granddaughter LOL. The original mama chewed a hole just big enough to squeeze her squirrley body through in the polycarb glazing by the greenhouse vent, and she makes a winter nest every year in the same place, up in a piece of driftwood mounted over the door. She has made free with my plant tags for years, and buried stuff in my pots and baskets. She does;t eat anything, but she has dug plants out of a pot, thrown them on the ground and used the pot to plant nuts in. Its maddening. I can't get mad though, she is just looking for a warm place to have her children. I tolerate her. But I think that the big black racer snake that lives in the greenhouse may actually eat some of her progeny.