Day two of the butterfly fiasco.

I took my little Lazarus outside and gently encouraged it to flutter off and find somewhere outdoors to hibernate. Alas, it just crawled forwards a few centimetres, then closed its wings and went back to sleep. It really is far too cold for it, and I don't think I can find any sensible places to put it. For now I've let it free in my room, and it's crawled up my windowsill and sat there not doing very much.

I'm really not sure what to do with the poor thing. On the one hand, the population of this species is in rapid decline, and I do want to let it free in the wild - but on the other hand, I'm fairly confident that in its current state it wouldn't survive the winter. What should I do, DQN?