Adaptations for Flight 1

Most bird adaptations are geared toward adaptations to flight: economy of weight, increased power, aerodynamic soundness.

To this last concern: a bird's mass is centered at wings and legs (= center of power), the size of limbs, head, and tail are reduced, and body weight is suspended under backbone to enhance stability.

Brown Thrasher.  Note the nictitating membrane covering the eye.