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
           Division Natatores Baird, 1858
             Subdivision Stegano-grallatores B.C. Livezey & R.L. Zusi, 2007
               Superorder Ciconiimorphae Garrod, 1874
                 Order Ciconiiformes Bonaparte, 1854
                   Suborder Scopi Bonaparte, 1853
                     Family Scopidae Bonaparte, 1853 - hammerkop