Vertebrata Cuvier, 1812 - vertebrates
   Gnathostomata
     Teleostomi
       Tetrapoda Hatschek & Cori 1896 [Gauthier, Kluge & Rowe 1988]
         Amniota Haeckel, 1866 [Gauthier, Kluge & Rowe 1988] - amniotes
           Class Aves Linnaeus, 1758 - birds see Subclass Aves Linnaeus, 1758
             Subclass Neornithes Gadow, 1893 see Clade Neornithes Gadow, 1893
               Superorder Neognathae Pycraft, 1900 see Cohort Neognathae Pycraft, 1900
                 Order Cuculiformes Wagler, 1830 - cuckoos and plantain-eaters
                   1 Family Opisthocomidae Swainson, 1837 - hoatzins
                   2 Family Musophagidae Bonaparte, 1831 - turacos
                   3 Family Cuculidae Vigors, 1825 - cuckoos