Birds are adapted for flying in several ways. Their forelimbs are specialized as wings covered with flight feathers; they have powerful wing muscles, a rigid body skeleton, light hollow bones, a large heart and a well-developed nervous system.
Think of the wings as being elongated arms (in the same way that you should think of the front legs of an animal as being like humans’ arms).
In order to generate the power required to fly, a bird must have huge wing muscles. These wing muscles ...