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 Passerae see Superorder Passerimorphae Sibley et al., 1988
         Superorder Strigimorphae see Superorder Falconimorphae Seebohm, 1890
           Order Strigiformes Wagler, 1830 - owls
             Suborder Strigi see Order Strigiformes Wagler, 1830
               Parvorder Strigida see Order Strigiformes Wagler, 1830
                 Family Strigidae Vigors, 1825 - owls
                   Genus Aegolius Kaup, 1829
                     Aegolius acadicus (J.F. Gmelin, 1788) - saw-whet owl
                       Aegolius acadicus acadicusᵀ (Gmelin, 1788) - northern saw-whet owl