Fledging wood pigeon in garden

We have a young wood pigeon appeared in the garden, parents are still around. It appeared about day ago, does not seem to have any obvious injuries, so leaving along for the moment.

But have noticed it does seem very unstable falls around rather than walking, but does sit upright with its wings folded.

My questions are;

Is this normal whilst it learns to stand, how long should i observe it like this before deciding to step in?

How long could it be on the ground for?