How big is a small squirrel compared to a big squirrel? I believe I have gray or black tree squirrels in my attic and I want to trap them out. I live in Toronto Ontario Canada and they're active most days. They seem to sleep most of the night but sometimes there I hear scratching just before dawn. There is a big walnut tree in the back park and I think they’re storing their nuts in my attic. Should I trap them in the attic or outside?