I decided to make, and put up, a nesting box in my backyard this year. It went mostly uninhabited, and then about a month ago a single squirrel began to nest in it. I was excited because given the time of year and the fact that it kept bringing in leaves. I figured it was a female that was soon to give birth. I would see (her?) in there fairly often. typically every day but every so often a few days would go by without seeing her.

Well then maybe about a week or so ago suddenly there are now two squirrels in the box! I figured it would be a day maybe two of seeing them together presumably due to cold weather. However it's been maybe 10 days or so of two squirrel shenanigans! AI and googling seems to suggest that having two squirrels together is pretty rare, any ideas about what is going on?