Martin,
Full marks for your effort in this. You are obviously an animal lover. I take my hat off to you.( or I would if I was wearing one ) I hope you manage to get a successful conclusion to this. If the bird is eating it may go home of it's own accord once it builds up it's strength. If it does it will be credit to you for helping out. You never know you could be a pigeon fancier of the future.
All the best,
Paul.
p.s if you ever fancy starting up there are plenty of guys on here to help.