Hatchlings & Nestlings
Bird feathers are very delicate and the natural oils on humans hands can strip them of their weatherproofing. Avoid handling and wear gloves.
Baby songbirds are altricial, which means they are defenceless without parental support. They are born naked without feathers, but sometimes with downy fluff. Their eyes are closed and they’re barely mobile.
If one is found on the ground, it may have simply fallen, been rejected, or poached from the nest by a predator or competitor. If you can locate and replace the baby back in the nest, this is the best; make sure it is warm first as a cold baby will be rejected. Songbirds learn who they are from their parents’ song; without this they may not develop and mature properly.