Males and female red-tailed black cockatoos can be distinguished by the splashes of colour on their tail feathers - red panels in males, and yellow-orange bars in females.
These cockatoos have zygodactyl feet, two toes facing forward and two backwards, that allow them to climb, and grasp objects with one foot while standing on the other.
They are sexually dimorphic: once they have come of age males turn solid black while females keep their speckled look.