Chances are if you see a baby bird on the ground, its mother and/or father are very close by, watching attentively, and chirping instructions. The young bird may spend a day or two on the ground before it takes its first flight.
Occasionally it really needs relocating; like if a dog or cat is nearby or it's in traffic. Go ahead and do so gently, putting it down in roughly the same area so the mother can keep teaching it how to be a bird. If you're worried about that silly old fable about a human's scent, don't even consider it. Truth is, most birds have a very poor sense of smell.
"Bunny Hugger" is a term for a well-meaning person who takes a wild animal home, and tries to raise it as a pet, often causing severe injury or death to the animal. Of course, a wild rabbit, bird, lizard, possum, squirrel or whatever is a wild animal, and always will be. Nobody knows better how to raise it than its natural mother.
The term was popularized in Thomas French's 2010 book, Zoo Story: Life in the Garden of Captives.