Why is the "standover man" portrayed as a bird?

The story is of a bird who is scared of men standing over him: the plot is identical to Max's own life. The first stand over man is his father, who vanishes at a young age. As a boy, he enjoys fighting, and whenever he loses another boy would be standing over him. When he comes to a safe house, it is a girl, not a man, standing over him. They share interests and the girl says he looks like something else. The girl asks the bird about his dreams and both his and Liesel's recurring nightmares are pictured: Max saying goodbye to his family, and Liesel sleeping with her younger brother at the side of her bed. The bird now thinks they are friends, and that on her birthday the girl gave a gift to him, a hug. The best stand over man he has ever known is not a man, but a girl. The idea of Max being represented by a bird suggestd that while he is physically caged in the basement, his spirit is free and proves indomitable by the Nazis. The stand over men in Max's life suggest his inner vulnerability: losing his father at a young age, for example, is compared with losing a fight. Yet a girl, not a man, standing over him brings him comfort as they become friends. Max has reached perhaps the most vulnerable point of his life thus far: he can continue to survive only at the mercy of the Hubermanns. His friendship with Liesel brings him such comfort that his best stand over man is a young figure of compassion, not antagonism, loyalty, and abandonment. 

A. i did this one at home when i was on the phone