Defferances

A wood pecker as 25 types of bone a human has 24

A woodpeckers bones are hollow but a humans is solid.

Size of creature wise the wood pecker has a thicker skull then humans because they bang their heads all the time.

All birds need a long and flexible neck because the Loss of forelimb usage so they use their beaks a lot but humans do not have long flexible necks.

The loss of the forelimb is because the limbs are mainly made for flying for example the wings humans do not have wings letting them use their forelimbs

Birds have feathers humans do not