Hello yes! A Science Birb, here to explain the science!
Birb have VERY LARGE EYE in skull. Very good for seeing! But not space for muscle, birb cannot move eye. For mammal to make steady image, keep focus on single thing, always moving eye! Tiny movements, sometimes not even know. But birb cannot make tiny movements! So, birb must move whole head. And that is why the birb can keep steady the head when the body is amovering!
Thank you for listening to a science
That was the greatest scientific explanation I have ever read