Subclass Avialae Gauthier, 1986 see Clade Avialae Gauthier 1986
Count: [o] 31o;113f; ‡2o;6f; †11o;14f
   Infraclass Aves Linnaeus, 1758 see Subclass Aves Linnaeus, 1758
  Count: [o] 31o;113f; ‡2o;6f; †11o;14f
     Parvclass Neornithes Gadow, 1893 see Subclass Neornithes Gadow, 1893
    Count: [o] 31o;113f; ‡2o;6f; †4o;7f
       Cohort Neognathae Pycraft, 1900
      Count: [o] 27o;107f; ‡3f; †4o;7f
         Subcohort Neoaves Sibley et al., 1988
        Count: [o] 25o;99f; ‡2f; †2o;4f
           Division Natatores Baird, 1858
          Count: [f†f] 8o;21f; †1o;1f
             Subdivision Pygopodo-tubinares B.C. Livezey & R.L. Zusi, 2007
            Count: [f] 4o;7f
               Superorder Gaviomorphae B.C. Livezey & R.L. Zusi, 2007
              Count: [f] 2o;2f
                 Order Gaviiformes Wetmore & Miller, 1926
                Count: [f] 1f
                   1 Family Gaviidae Allen, 1897 - divers
                  Count: -