I often see two or three of them chasing each other. I think I've seen four at once occasionally. We seem to have a thriving population of fox squirrels.

Grays haven't managed to establish, though. It would be fun to have both, as they like slightly different habitats. We had an adult gray for year or two, but only the one. This fall, a young one appeared, but I only saw it a few times and suspect that something ate it. :(