Baby fledgling found on ground.

Guys, hopefully someone can assist, just got back home after a walk. And there's a baby fledgling on the ground, and still alive. 

I don't know if the neighbours cat had got hold of him from a nest, or got thrown out of his nest. I'm going with the former.

Believe it's a starling, brown with beige specs, size of a chick. Surely not old enough yet to fly the nest?

Got it in a shoe box with tissue at the moment, question is, what do I do? What do I feed it? How do I care for it? 

Help!