Advice about an injured goldfinch chick...

Hello everyone!

I'm wondering if anyone might be able to give me advice about what (if anything) to do about an injured goldfinch chick in our garden.  I came across him just sitting on the ground immobile, and he seems to have a bit of a bloodied head.  He was very still, and I thought he wasn't going to make it.  However, I put out a wee saucer of water and he's climbed onto that - not drunk anything mind! But now he is moving about a bit - just walking, hopping, looking around.  Feathers are still very pluffed up.  He can't seem to fly at the moment, though I assume he must have flown into the garden so perhaps just a bit concussed...

Should we just keep an eye on him and let im be (he's on the ground, in the middle of a garden, so pretty vulnerable...).  Or would he benefit from having a well-ventilated box put over him so he's safe and can rest a little while (but I guess also then parents can't get to him if they want to...)

Any advice or thoughts would be very much appreciated...

Thank you!

Lori