Class Aves Linnaeus, 1758 - birds see Subclass Aves Linnaeus, 1758
   Subclass Neornithes Gadow, 1893 see Clade Neornithes Gadow, 1893
     Infraclass Neoaves Sibley et al., 1988 see Subcohort Neoaves Sibley et al., 1988
       Parvclass Galloanserae Sibley, Ahlquist & Monroe Jr., 1988 see Subcohort Galloanserae Sibley, Ahlquist & Monroe Jr., 1988
         Superorder Anserimorphae see Order Anseriformes Wagler, 1831
           Order Anseriformes Wagler, 1831 - waterfowl and screamers
             Infraorder Anserides see Suborder Anseres Linnaeus, 1758
               Family Anatidae Vigors, 1825 - ducks, geese, swans
                 Subfamily Anatinae Vigors, 1825 - pond ducks
                   Tribe Anserini Vigors, 1825 - geese see Subfamily Anserinae Vigors, 1825
                     Genus Tadorna Boie, 1822
                       1 Tadorna ferruginea (Pallas, 1764) - ruddy shelduck
                       2 Tadorna cana (Gmelin, 1789) - South African shelduck
                       3 Tadorna tadornoides (Jardine & Selby, 1828) - Australian shelduck
                       4 Tadorna variegata (Gmelin, 1789) - paradise shelduck
                       5 ‡Tadorna cristata (Kuroda, 1917) - crested shelduck
                       6 Tadorna tadorna (Linnaeus, 1758) - common shelduck
                       7 Tadorna radjah (Lesson, 1828) - radjah shelduck