There are at least three major lineages of barn owl: the western barn owl of Europe, western Asia, and Africa; the eastern barn owl of southeastern Asia and Australasia; and the American barn owl of the Americas. Some taxonomic authorities classify barn owls differently, recognising up to five separate species; and further research needs to be done to resolve the disparate taxonomies. There is considerable variation of size and colour among the approximately 28 subspecies, but most are between 33 and 39 cm (13 and 15 in) in length, with wingspans ranging from 80 to 95 cm (31 to 37 in). The plumage on the head and back is a mottled shade of grey or brown; that on the underparts varies from white to brown and is sometimes speckled with dark markings. The face is characteristically heart-shaped and is white in most subspecies. This owl does not hoot, but utters an eerie, drawn-out screech.