hi NCA ... good to see you again.
I've been keeping an eye out daily and I haven't seen anything to indicate an 'serious' intruder. She's relaxed, she's preening - things she wouldn't be doing if there was a real threat. Are there migrating birds / floaters passing through? Sure it's that time of year so there could very well be some posturing at the nest boxes just to show them this house is taken, move along

DC being around more is likely because he's not doing double duty this year and he's impatient for eggs.
ps: I should add that's all I hope it is anyway. After all, I can't see beyond the perimeters of the cameras.