Dear "3dbb4nmo" How nice of you to try and rescue this baby bird you found on the pavement who is acting dizzy, spinning in circles and can't fly.
It is common for baby birds to fall out of their nest. Unfortunately, it can be difficult to care for them. The best thing you can do is try and return him to the nest if you can find it. Look up in the area where you found him and see if you can find a nest. If so, try to get him back into the nest. I realize this may be impossible because you may not find a nest or the nest may be out of reach.
If you can't return him to his nest, he will need to be hand raised and his injuries will need to be addressed. You can take him to the closest veterinary emergency hospital for tonight. They may be able to give him supportive care until he can be transferred to an experienced avian rehabilator. I would put him in a nice box with a towel and take him to an emergency facility and drop him off.
If this is not possible, you can keep him in a warm box with a towel on the bottom and some nesting material (shredded paper). You can buy juvenile bird hand feeding formula at most pet stores and a feeding syringe. The pet store associates can advise you on how to hand feed the bird depending on what type of hand feeding formula they are selling. It can be very difficult to hand feed a baby bird if you've never done it before but if you are willing to try and can't take him to an emergency facility or return him to his nest, trying to hand feed is the next-best option.
I hope this is helpful information.
Please let me know if you have more questions. I am happy to continue this conversation until all of your questions are completely answered.
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Take care and you're very nice to help this stranded bird.
He may be acting dizzy due to an injury (i.e. flew into a wall or window), an illness such as infection or parasites, or other medical problem. If he is not a baby, it is likely some type of trauma. I usually give these birds pain medication, sometimes a low dose of steroids, and keep them warm in an incubator when people bring them to my hospital. That is what I am hoping an emergency facility will do if you bring him.