The western barn owl's subspecies consists of the T. a. alba which have been identified all over the world except the British Isles, a group of islands in the North Atlantic that have an area of 315,159 kilometers.
T. a. guttata (C. L. Brehm, 1831) In flight, Sandesneben (Germany) T. a. poensis (Fraser, 1842) T. a. thomensis (Hartlaub, 1852) T. a. affinis (Blyth, 1862) In Tanzania T. a. schmitzi (Hartert, 1900) T. a. ernesti (Kleinschmidt, 1901) T. a. gracilirostris (Hartert, 1905) T. a. detorta (Hartert, 1913) T. a. erlangeri (W. L. Sclater, 1921) T. a. alba (Scopoli, 1769) Light-coloured adult Western Europe from the British Isles south to the Maghreb and west along Mediterranean coastal regions to northwestern Turkey in the north and the Nile in the south, where it reaches upstream to northeastern Sudan. Also the Air Mountains in the Sahara of Niger, the Balearic Islands and Sicily in the Mediterranean, and the West Canary Islands (El Hierro, La Gomera, La Palma Gran Canaria and Tenerife). Intergrades with guttata from the Balkans through Hungary and along the Rhine and lower Meuse rivers, and with affinis around the Egypt-Sudan border. 
