Found A Budgie, Help!

Hello, last night we were driving down a semi rural road and saw what we thought was a canary that had escaped. I stopped, walked up to this little "canary" and picked it up, and put it in a shoe box and brought it home. We have tried to find its owners to no avail.

I have since worked out he is actually a yellow budgie. We have borrowed a bird cage from a friend and are happy to keep him but I'm a bit mortified that maybe I picked up a wild bird and brought him home!! What are the chances? I figure he must have been a pet since he was so timid - but also looking quite frazzled I have to say on the side of the road.

He's been happy as at our place, chirping away and eating and drinking. Turns out he loves kale from our veggie patch.

Anyway...we have called him Lucky.

Lucky is all yellow with white cheeks and a bright blue cere (above the beak, yes?) I think Lucky is a boy, am I right? Any way of telling how old he is?

And...he seems to have a bit of a sore on his wing. What is your advice about this? When I work out how to post his picture on here I will.

Thanks all!