Here's the third update of the butterfly saga (because I'm sure you were all so worried).

The butterfly is still alive and active, however it seems to be having great difficulty flying; it just twitches its wings a little every so often, as though it's trying to fly but its muscles are too weak, or something. I suppose it has (presumably) just come out of hibernation, to be fair.

I have come to the conclusion that I really can't come up with any sensible place to leave it to hibernate. Ideally, if it becomes strong and active enough to fly, then I'll let it go and it can find its own place, which will be much better than anywhere I could find for it. Otherwise, I'll just let it stay on my windowsill until it dies, and keep its corpse as a memento.