Instructions
The first thing you should try to do is put the baby back in its nest. My brother's kids once found a baby crow and they couldn't find it's nest so they decided to try to raise it. When I was younger we raised a baby raven and a baby magpie and it was a romantic thought in the beginning, but it didn't take us long to gain an appreciation for how hard those bird parents actually work to keep their young fed. So if at all possible please take a minute and find the nest. Put it back in and keep an eye out for mom and dad.
If there is no nest to be found then it's time to pull out the home box collection. If you have a heat lamp or light you will need one to help keep the orphan warm until its feathers grow in. In the wild these little babies get worms and all sorts of bugs to eat. Try to get them as much of this sort of food as possible. If the baby you found is a predatory bird then you will need to catch and chop up mice to feed it. Eventually you will notice that it is challenging to maintain a steady supply of protein rich food for these growing babies so there is another option.
Keep feeding them what you can naturally find in your back yard, but what worked best for us, was canned dog and cat food. The baby birds get the water they need out of the food you bring them, but when they get bigger they will need a good supply of drinking water. Eventually our Raven and Magpie just ate out of the dog bowl, but eventually your little orphan may return to the wild and start selecting it's diet off of Mother Nature's menu. Do the best you can to provide for your orphans, but don't be to upset if they die on you. They are very delicate when young and need lots of attention. Some never return to the wild, because they have identified with humans and so they will always see you as their parent(s).
My father raised a Great Horned Owl, a Barn Owl, and a Red Tailed Hawk when he was younger and it was a family affair to keep these great predatory bird's stomachs full of fresh mice and gophers. If you can't keep them in the nest then let their parents raise them, but if you do have to care for orphaned birds then please do your best, or call your local wildlife agency and seek their counsel or assistance. Some birds are illegal to keep so keep that in mind as well. Read up all you can on the internet for bird rescue tips. Good Luck!
How to Care For Orphaned Birds
I won't lie. It is challenging to care for orphaned birds, especially when they are youngest. Some baby birds like ducks, geese, quail and chickens are naturals at scavenging for food, but others aren't so lucky. They have to be fed for a time before they even grow their down. They are born naked. These are the orphans that this article considers. I will tell you exactly what you need to do to raise these baby orphans.