Squirrel -- just curious?

This may sound silly, but I hope a person who knows about wildlife will know the answer. We have a squirrel in our yard whom we've named Buddy. It lives in the brush under a rock and is furiously digging holes and shredding pinecones in preparation for winter. It's very territorial and drives all other squirrels away from the area. My question is, is Buddy more likely a male or a female? It's definitely alone and is probably getting ready to hibernate. I don't know when mating would occur.

If you happen to know, I'd appreciate learning something about squirrels! Thanks!