The Yellow-headed amazon, also known as the Double Yellow-headed amazon, seems to be the best known of the Amazon parrots. This species has a yellow nape as well as a yellow crown, which is why it has "double-yellow" in its name. The yellow color increases with age and some birds have completely yellow heads when they are just a few years old. The majority, however, take longer, each molt resulting in an increase of the yellow on the bird's head. They use their stout hooked beak for cracking seeds and nuts, and also for grasping and climbing. Their feet are also well adapted for grasping, with two toes facing forward and two facing backward.