Raccoon!

Uh-oh 3am.  Loud noises downstairs.  I'm terrible at being able to locate the source of a sound.  This is clearest when I call my phone to locate it and can't figure out where it's ringing.

I mention this only to point out that I was fairly certain the noise was downstairs but couldn't swear it wasn't upstairs.

Turned on the stairway light and could see that the raccoon had pushed aside the insulation and the wooden box I'd propped up against the opening.  Had it come upstairs again?  I did not know.

I did a little internet research on raccoon visitations (they often use houses as nesting areas, but this is not the breeding season and usually come in looking for food--generally garbage or pet food).

I convinced myself I had nothing to fear and putting on my shoes headed downstairs to make sure there were no raccoons happily snacking in the kitchen.

I had some vague thoughts of opening a door and letting the raccoon out--maybe I had that thought--I'm not quite sure.

But I think the raccoon might have exited on its own.  When he removed the floor boards, Johnny had leaned the metal baseboard covers from the heating pipes agains the wall.  They had been knocked down as had the fire screen.  That crashing to the floor woke me up and probably sent the raccoon on its way.

I re-stuffed the insulation so I will know if it returns but will have to get this hole closed up as soon as possible.  I'm assuming the raccoon will not be trapped under the house, but will address that question in the light of day.