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 Glaucidium Boie, 1826
                     01 Glaucidium passerinum (C. Linnaeus, 1758) - Eurasian pygmy-owl
                     02 Glaucidium brodiei (E. Burton, 1836) - collared owlet
                     03 Glaucidium perlatum (Vieillot, 1817) - pearl-spotted owlet
                     04 Glaucidium californicum Sclater, 1857 - northern pygmy-owl see Glaucidium gnoma californicum Sclater, 1857
                     05 Glaucidium gnoma Wagler, 1832 - mountain pygmy-owl
                     06 Glaucidium jardinii (Bonaparte, 1855) - Andean pygmy-owl
                     07 Glaucidium bolivianum König, 1991 - Yungas pygmy-owl
                     08 Glaucidium hardyi Vielliard, 1989 - Hardy's pygmy-owl
                     09 Glaucidium minutissimum (Wied, 1830) - least pygmy-owl
                     10 Glaucidium brasilianum (J.F. Gmelin, 1788) - ferruginous pygmy-owl
                     11 Glaucidium peruanum König, 1991 - Peruvian pygmy-owl
                     12 Glaucidium nanum (P.P. King, 1828) - austral pygmy-owl
                     13 Glaucidium siju (d'Orbigny, 1839) - Cuban pygmy-owl
                     14 Glaucidium tephronotum Sharpe, 1875 - red-chested owlet
                     15 Glaucidium sjostedti Reichenow, 1893 - Sjostedt's owlet
                     16 Glaucidium cuculoides (Vigors, 1831) - Asian barred owlet
                     17 Glaucidium castanopterum (Horsfield, 1821) - Javan owlet
                     18 Glaucidium radiatum (Tickell, 1833) - jungle owlet
                     19 Glaucidium castanonotum (Blyth, 1852) - chestnut-backed owlet
                     20 Glaucidium capense (A. Smith, 1834) - African barred owlet
                     21 Glaucidium castaneum Neumann, 1893 - chestnut owlet see Glaucidium capense castaneum Reichenow, 1893
                     22 Glaucidium ngamiense (Roberts, 1932) - Ngami owlet see Glaucidium capense ngamiense (Roberts, 1932)
                     23 Glaucidium scheffleri Neumann, 1911 - Scheffler's owlet see Glaucidium capense scheffleri Neumann, 1911
                     24 Glaucidium albertinum Prigogine, 1983 - Albertine owlet see Glaucidium capense albertinum Prigogine, 1983