Where did all the squirrels go?

I can't believe I didn't see a single squirrel this weekend! Usually there are a lot of them running up and down the large oak trees in my front yard but, this weekend I couldn't seem to find any. Maybe I was looking to hard. I'm assuming if I did see any they would be the Gray because from the description it sounds the most familiar.
Even though I wasn't able to spot any squirrel's I did notice that the leaves are beginning to fall. This surprised me a little bit, seeing as the weather has been so strange. Hopefully this is a sign that it will be cooling off!