parrot - It is unquestionable that the Psittaciformes consist of 2 major lineages of family rank: the true parrots (Psittacidae) and the cockatoos (Cacatuidae). The Cacatuidae are quite distinct, having a movable headcrest, different arrangement of the carotid arteries, a gall bladder, differences in the skull bones, and lack the Dyck texture feathers which, in the Psittacidae, scatters light in such a way as to produce the vibrant colours of so many parrots