It's getting late and I'm not sure what else I can do. I'm looking up other animal/wildlife numbers to call in the phonebook to see if anybody else can help, but in the off chance I can't get through/get anyone, is there any advice anybody can give me into making sure the bird can survive the night? It seems well enough and mobile right now, except that it can't/won't fly.
Edit: Can't get through to anybody, so I put a wrapped up heatpad into the box and put the bird on top of it so it can stay warm for now. I'll feed it some honeyed/sugared water later on, and again before I go to bed. Thanks for the advice everyone, I'm just going to hope it can survive and take it down to one of the centers tomorrow to see if they can help it better than I can.