Basically, my cat brought home a baby bird yesterday which was still alive. We put it into an open, Styrofoam box layered with a soft towel.

We've been feeding it worms since yesterday night, but we honestly dont know if he'll survive.

So i carried him with the box and put him into a nearby pine tree with a random nest above it (which i cant reach, which is why i put it below it). That was an hour ago.

I checked back on him about 10 minutes ago and he's still there, no parents to pick him up.

My ZIP code is 44147, i need to know if what i did is the right thing and if i should leave him in that pine tree, whether he'll die or not. What would you advise me to do?

Its great that you're taking care of him, but he needs to be brought to a professional. Often when a baby bird falls or is taken from a nest, the mother will not return to the nest, even if she is raising other young. The baby bird has little to no chance of surviving on its own. pets question and answers,www.5d2d.com
Your best bet would be to bring the bird to a wildlife rehabilitator - someone who specializes in the care and rehabilitation of wild animals that are somehow incapable of survival on their own. Check your local yellow pages or look online to see if there's one near where you live. I've had experience with a lady who works in wildlife rehabilitation in the past (I have outdoor cats too, haha) and she has been great.

Personal experience

Sadly you should let nature take it's course. Without it's parents it likely wont survive and probably starve. The cat could have injured it in such a way it won't be able to fly.
what i would do is either: 1)easy thing, just let die. 2) Hard thing, go and put it out of it's misery.
i know that sounds awful. but you are doing it a favor by not letting it die slowly and painfully

Bring it in and put it in a box with some newspaper or cloth, keep it safe... call one of the local wildlife rehabilitation centers in your area. Follow their advice. pets question and answers,www.5d2d.com
http://www.ohiowildlifecenter.org/
http://backtothewild.com/ (recomended link)
http://www.natures-nursery.org/

here are 2 choices

1.take back because it can not survive without you and now that your scent is on it mother will not feed it or take it back

2.call animal shelter/rescue and get them to pick it up or you can drop it off

I would wait to see if his mom bird comes back if not take him in and feed him until he can fly

You probably shouldn't just leave him. Finding his parents would give him the best chance of survival, yes, but the parents will only find the bird if it's left very near its nest; because your cat brought it, you have no idea where its nest is. So more than likely, they won't find it before it dies. See if your area has a wildlife rehabilitation group; if so, trained volunteers can take care of the bird for you and give it a much better chance of survival. pets question and answers,www.5d2d.com

But, if you're left raising it yourself, do the best you can. Has it been eating the worms? If so, that probably means that's a natural food source for it and you should keep feeding the worms. Offer a source of water as well. If you can, try to identify it by searching the web, books, or (probably the best choice) asking someone who is knowledgeable about area birds. This will help you know more specifically the best way to care for it.

Good luck... baby birds often die, but on occasion, it's possible to raise them to adulthood. Good luck.