Nestlings (baby birds without feathers) should not be out of the nest and will need help. Where possible they should be returned to their nest (make sure it’s the right one!), you can find further advice on the RSPCA website here.
But, if you ever find a garden bird fledgling (fully feathered baby bird) on the ground, if they’re not sick or injured they’re usually best left alone.
They intentionally leave the nest before they can fly, and their parents are usually nearby and still caring for them. Parents may even be waiting for people to leave before they return to their young. It’s normal for fledglings to be on the ground between a few days to a week or so whilst they finish growing their flight feathers.
During this time, please keep people and pets away, and leave the fledgling undisturbed and in the care of their parents. Remember that birds take far better care of their young than humans can. Taking baby birds into captivity can dramatically reduce their chances of long-term survival.
If they’re in a position of danger, fledglings can be moved to a nearby sheltered, safe place such as under a hedge. They still need to be within hearing range of where they were found, as parents often use calls to locate their young. Watch the fledglings from a distance until you have seen the parents find them.