Subclass Avialae Gauthier, 1986 see Clade Avialae Gauthier 1986
   Infraclass Aves Linnaeus, 1758 see Subclass Aves Linnaeus, 1758
     Parvclass Neornithes Gadow, 1893 see Subclass Neornithes Gadow, 1893
       Cohort Neognathae Pycraft, 1900
         Subcohort Neoaves Sibley et al., 1988
           1 Division Natatores Baird, 1858
           2 Division Terrestrornithes B.C. Livezey & R.L. Zusi, 2007