Little Baby Starling?

We had a very old birdhouse sitting on top of a very old pole, My little brother decided it would be a good idea to shake the pole so the birdhouse fell off and inside was a baby starling. I had an old Rat cage and that's where it is right now. I don't know how old it is but it has it's adult feathers and I need to know how to feed it and what it likes best.