The taxonomy of certain Asio and Bubo owl species in Africa and Arabia

We reconsider the cases of certain large owl taxa with mainly African ranges whose taxonomic status is unsettled, reviewing plumage, morphometric and acoustic evidence. Abyssinian Owl Asio abyssinicus differs from Long-eared Owl A. otus in being roughly 15% larger with several plumage distinctions and a
markedly shorter song-note or hoot (although the voice of A. a. graueri of the equatorial Rift Valley is not certainly known). Pharaoh Eagle Owl Bubo ascalaphus differs from Eurasian Eagle Owl B. bubo in being c.15% smaller with several plumage distinctions (including no heavy streaks below the breast) and a higherpitched but also different-shaped territorial call. Greyish Eagle Owl B. cinerascens differs from Spotted Eagle Owl B. africanus by its iris and eyelid colour, softer, greyer markings, smaller size and shorter double song-notes or hoots with longer intervals between them. The Arabian form milesi, commonly treated as a subspecies of Spotted Eagle Owl, is smaller than africanus with less contrasting plumage and a distinctive double song-note or hoot, the first of them much longer, the second on the same pitch and quavering; it
differs from cinerascens in its iris and eyelid colour, less distinctive plumage, slightly larger size and voice (even more divergent than it is from africanus).