If a mommy bird gets scared by human and flies away will she ever come back?

In most cases, yes, a mommy bird will come back to her nest if she gets scared away by a human. Birds have a strong desire to care for their young, and they will usually return to their nest after a brief period of absence. However, there are some exceptions to this rule. If the nest is destroyed or if the baby birds are too old, the mother bird may not return. Additionally, some species of birds are more likely to abandon their nests than others. If you find a nest with baby birds in it, it is best to leave it alone and give the mother bird a chance to return.