Just rescued a bird

[MondyJim]

Hi all, just managed to get a little bird out of the jaws of one of our cats. When I picked it up, it was really gasping for breath but after a few minutes of holding it it seemed to calm a little and then opened it's eyes. It looks like a really young bird, it's still got really fluffy down rather than proper feathers. It wasn't stretching it's wings so I assume it can't yet fly. We've put it in a box in the garage with a load of rags for it to keep warm in, plus some wild bird seed (although I reckon it might be too young to eat this) and a little tub of water.
My question is, is there anything more we can do other than just wait and see how it is doing in the morning? What can we give it to eat for strength before it learns to fly?
Sorry for the long post.

[mybrainhurts]

It won't need a long post yet.