Belongs within: Strigidae.
Strix is a genus of medium-sized to very large owls lacking external ear-tufts, found widely in Eurasia, Africa and the Americas. The tawny owl S. aluco is a medium-sized species that is widespread across the western Palaearctic.
<==Strix Linnaeus 1758CC10 [incl. Ptynx Blyth 1840B94, Syrnium Savigny 1809B94, Ulula Cuvier 1816B94; Syrniinae, Ululinae] |--+--+--S. occidentalisBKB15 | | `--S. virgataJT12 | `--+--S. rufipesBKB15 | `--S. variaBKB15 `--+--+--S. butleriBKB15 | `--S. woodfordiiBKB15 `--+--+--S. leptogrammicaJT12 | | |--S. l. leptogrammicaA72 | | |--S. l. connectensA72 | | |--S. l. indraneeA72 | | |--S. l. newarensisA72 | | |--S. l. ochrogenysA72 | | `--S. l. shanensis Baker 1935A72 | `--S. nebulosaBKB15 [=Ulula nebulosaJ23] `--+--S. aluco Linnaeus 1758BKB15, CC10 (see below for synonymy) | |--S. a. alucoRN72 | |--S. a. biddulphiA72 | |--S. a. nivicolaA72 | |--S. a. sylvaticaRN72 | `--S. a. wilkonskiiRN72 `--+--S. davidiBKB15 `--S. uralensisBKB15 Strix incertae sedis: S. albitarsisJT12 S. atricapillaP89 S. chacoensisJT12 S. dakotaFP64 S. edwardsi Ennouchi 1930 [=Tyto edwardsi]M02 S. fulvescensJT12 S. hudsonia [=Noctna hudsonia]J23 S. huhulaJT12 S. hylophilaJT12 S. ignota Milne-Edwards 1871 [=Tyto ignota, Asio ignotus]M02 S. nigrolineataJT12 S. ocellataJT12 |--S. o. ocellataA72 |--S. o. grandisA72 `--S. o. grisescensA72 S. otus Linnaeus 1758L58 [=Otus otusJ23] S. phalaenoides [=Noctna phalaenoides]J23 S. poensis Fraser 1842F42 S. seloputoJT12 S. virgiana [=Otus virgianus]J23 S. wintershofensis (Ballmann 1969) [=Otus wintershofensis]M02
Strix aluco Linnaeus 1758BKB15, CC10 [=Syrnium alucoCC10, Smyrnium (l. c.) alucoCC10; incl. Strix intermedia Jánossy 1972M02, *Strix stridula Linnaeus 1758B94]
*Type species of generic name indicated
References
[A72] Abdulali, H. 1972. A catalogue of the birds in the collection of the Bombay Natural History Society—11. Strigidae and Caprimulgidae. Journal of the Bombay Natural History Society 69 (1): 102–129.
[B94] Bock, W. J. 1994. History and nomenclature of avian family-group names. Bulletin of the American Museum of Natural History 222: 1–281.
[BKB15] Burleigh, J. G., R. T. Kimball & E. L. Braun. 2015. Building the avian tree of life using a large-scale, sparse supermatrix. Molecular Phylogenetics and Evolution 84: 53–63.
[CC10] Checklist Committee (OSNZ). 2010. Checklist of the Birds of New Zealand, Norfolk and Macquarie Islands, and the Ross Dependency, Antarctica 4th ed. Ornithological Society of New Zealand and Te Papa Press: Wellington.
[FP64] Fisher, J., & R. T. Peterson. 1964. The World of Birds: A comprehensive guide to general ornithology. Macdonald: London.
[F42] Fraser, L. 1842. On two new species of birds from western Africa, belonging to the genera Strix and Pitta. Proceedings of the Zoological Society of London 10: 189–190.
[J23] James, E. 1823. Account of an Expedition from Pittsburgh to the Rocky Mountains, performed in the years 1819 and ’20, by order of the Hon. J. C. Calhoun, sec’y of war: under the command of Major Stephen H. Long. From the notes of Major Long, Mr. T. Say, and other gentlemen of the exploring party vol. 1. H. C. Carey & I. Lea: Philadelphia.
[JT12] Jetz, W., G. H. Thomas, J. B. Joy, K. Hartmann & A. Ø. Mooers. 2012. The global diversity of birds in space and time. Nature 491: 444–448.
[L58] Linnaeus, C. 1758. Systema Naturae per Regna Tria Naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. Laurentii Salvii: Holmiae.
[M02] Mlíkovský, J. 2002. Cenozoic Birds of the World. Part 1: Europe. Ninox Press: Praha.
[P89] Parona, C. 1889. Sopra alcuni elminti di Vertebrati birmani raccolti da Leonardo Fea. Annali del Museo Civico di Storia Naturale di Genova, Serie 2a, 7: 765–780.
[RN72] Rutgers, A., & K. A. Norris (eds.) 1972. Encyclopaedia of Aviculture vol. 2. Blandford Press: London.