Please, please, please do not “rescue” baby birds if they are covered in feathers. They are fine: they are hiding, and being fed by their parents, and growing, and soon they will be able to fly even if they can’t yet. If you find a naked pink baby bird, and can’t see the nest it fell out of and put it back, then please use the internet to find a local wildlife rehabilitator and bring the animal to them. They know how to keep baby birds alive. It is difficult. If you try to raise a baby bird yourself, without specialized knowledge, it will probably die. I volunteer at a wildlife rehabilitation hospital, and our care of baby birds is complicated, from determining the diet to the amount to the best way to house and eventually release them. We are constantly advised by trained veterinarians. This is not something you should be trying to do at home unless, for some reason, there is absolutely no way to get the animal to a rehabilitator (maybe you live on a tiny island in the middle of the ocean?), and even then, you should contact a rehabilitator and ask for advice. Don’t just try to guess. You will guess wrong.
I know you want to help. I know you mean well. But good intentions will not prevent you from killing a baby bird. And then you comment on this blog to ask me why it died, and I get so many of these comments, so many stories of people accidentally-but-avoidably killing birds, and it makes me dread checking the comments on this blog in case there is another one of these stories. The baby bird died because you are not a bird and not a trained wildlife rehabilitator. Let the birds raise their babies.
I covered this is in this older post, including ways that you can help birds.
This wildlife rehabilitator has a good article on how to tell if an animal needs your help.