Sudden Aggression?

[Asos]

Not sure if I should start a new thread, but my original thread kind of fell by the wayside. (https://thesquirrelboard.com/forums/...s-from-NE-Ohio!)

I have 2 babies, my first ones. Clyde (male) is now 10 weeks and was raised from a few days old and Bean (female) who was given to me orphaned at an estimated 8 weeks -- she is now estimated to be 12 weeks. Bean has been more wild, but always friendly. They are still drinking formula (FV 20/50) as much as they'd like 3x per day and getting Henrys blocks and Mazuri rodent blocks offered in the morning (they dont like the mazuri), fresh veggies at lunch time and in the evening, along with formula.

I made them a nesting box and put it in their cage this weekend and they've slowly been checking it out and putting some nesting things inside. They still have their original cardboard nesting box on the floor of the cage too. Well... I went home at lunch today and gave them their veggies and reached up toward the new box that they were both in to give Bean a leaf and she started lunging at me! She was chattering her teeth and making angry squirrel noises too.. It broke my heart! I have to overwinter them.. so I am concerned about this. She scratched me (no big deal) but didn't seem to be attempting to bite. Usually she happily takes new foods from me.

My cat ran in the room a few minutes prior, but was only in there for a few seconds. I know the dangers, the door is always shut and the cage closed. Could she have been freaked out by him? Was it bad that I put the nesting box in and it's making her too territorial? I also had a beanie hat on, but she didnt change her attitude when I removed it. I usually wear hoodies with them anyway due to the crazy climbing. i dont want her to put Clyde in danger, or attack me for the 6-8 months..

Any words of wisdom from experienced overwinter-ers? See photos of the box and Bean below: