In general, species feeding on carrion, like turkey vultures, show no sexual dimorphism. B. Body shape. This body shape reduces drag while flying. Most diurnal birds of prey have subdued feather colors, mainly browns, rust, black, white, and some blues and grays. Males and females are usually identical in color except in some harriers and falcons.
Many species have an immature plumage and an adult plumage.
Immature bald eagles are completely brown in coloration, while adults have a distinctive white head and tail. This polymorphism seems to be related to habitat. In red-tailed hawks, dark colored birds are more common in the open country of the western U.S., while light colored birds are more prevalent in the forested areas of the eastern U.S. D. Limbs. The forelimbs of birds are modified into wings. Wings are covered with feathers, providing a lightweight surface for lifting and propelling a bird in flight.