Neornithes Gadow, 1893 - living birds
   Neognathae Pycraft 1900 see Cohort Neognathae Pycraft, 1900
     Neoaves Sibley et al. 1988 see Subcohort Neoaves Sibley et al., 1988
       [Order] Charadriiformes Huxley, 1867 - shorebirds, gulls, auks
         Family Laridae Vigors, 1825 - gulls, terns and skimmers
           Subfamily Larinae Vigors, 1825 - gulls
             Genus Larus Linnaeus, 1758
               Larus occidentalis Audubon, 1839 - western gull
                 Larus occidentalis wymani Dickey & van Rossem, 1925