Has the bird made its way outside now?
Yes, the poor thing. I tiptoed as gracefully as I could over to the window and opened it as wide as it would go, then I found a spot to sit and watch, as far removed from the bird's exit as I could comfortably get. It took three or four approaches, but it finally found its way out.
Heehee!
I was going to say the chimney, could that have come unsealed?
What kind of bird?
There is nothing between the tiled-over roof and where the flue would enter the hearth area (if we had one). The loft floor is covered over... all internal traces of the chimney/flue system have been removed. I'm pretty sure that was not his way in.
Hmm... but that reminds me... a sound startled me last night and something that had no business falling fell from the mantle. I picked it up and replaced it, and all was quiet in the house after that. Maybe it was the bird, though... maybe he was in the house all night (I still don't know how he would've got in!).
I don't know birds, but I recorded some video of him hopping around my untidy bedroom... I will switch to my laptop (affectionately referred to as my "big phone" because I use my mobile and my laptop pretty much the same way) so I can upload an image or gif or video.