What should you do if you find an injured bird?

You should go to a website that tells you what to do right now as far as feeding it and the right temperature for it. Then, if you have a vet school anywhere near, they'll take it into their bird clinic for free. If you don't have a vet school around, I guess you should ask a local small animal vet. You could also check with the humane society.
I found an abandoned baby rabbit a few weeks ago and I did this stuff. There are tons of websites on animal care.

I hope it does okay.