Skeletal Muscles

The meat of chicken breasts is considered white meat, whereas chicken legs and thighs are made up of dark meat. However, the breast and leg meat of migrating ducks are composed of dark meat. The breasts of chickens and ducks are used in flying. How can you  explain the differences in color of the muscle meat? How are they adapted for their particular functions? Be sure to use proper terminology when referring to the various types of skeletal muscle fibers.