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The Eurasian eagle-owl (''Bubo bubo'') is a species of eagle-owl that resides in much of Eurasia. It is sometimes called the European eagle-owl and is, in Europe, where it is the only member of its genus besides the snowy owl (''B. scandiacus''), occasionally abbreviated to just eagle-owl.〔Andrews, P. (1990). ''Owls, caves and fossils: predation, preservation and accumulation of small mammal bones in caves, with an analysis of the Pleistocene cave faunas from Westbury-sub-Mendip, Somerset, UK''. University of Chicago Press.〕 It is one of the largest species of owl, and females can grow to a total length of , with a wingspan of , males being slightly smaller.〔''Owls of the World: A Photographic Guide'' by Mikkola, H. Firefly Books (2012), ISBN 9781770851368〕 This bird has distinctive ear tufts, with upper parts that are mottled with darker blackish colouring and tawny and the wings and tail are barred. The underparts are a variably hued buff, streaked with darker colour. The facial disc is poorly developed and the orange eyes are distinctive. Besides being one of the largest living species of owl, it is also one of the most widely distributed.〔Hume, R. (1991). ''Owls of the world''. Running Press, Philadelphia, PA. 1991.〕 The Eurasian eagle-owl is found in a number of habitats but is mostly a bird of mountain regions, coniferous forests, steppes and other relatively remote places. It is a mostly nocturnal predator, hunting for a range of different prey species, predominately small mammals but also birds of varying sizes, reptiles, amphibians, fish, large insects and other assorted invertebrates. It typically breeds on cliff ledges, in gullies, among rocks or in some other concealed locations. The nest is a scrape in which averages of two eggs are laid at intervals and which hatch at different times. The female incubates the eggs and broods the young, and the male provides food for her and when they hatch, for the nestlings as well. Continuing parental care for the young is provided by both adults for about five months.〔Voous, K.H. 1988. ''Owls of the Northern Hemisphere''. The MIT Press, 0262220350.〕 There are at least a dozen subspecies of Eurasian eagle-owl. With a total range in Europe and Asia of about 32 million square kilometres (12 million square miles) and a total population estimated to be between 250 thousand and 2.5 million individuals, the IUCN lists the bird's conservation status as being of "least concern".〔(【引用サイトリンク】title=Bubo bubo )〕 Tame eagle-owls have occasionally been used in pest control because of their size to deter large birds such as gulls from nesting. ==Description== The Eurasian eagle-owl is a very large bird, smaller than the golden eagle (''Aquila chrysaetos'') but larger than the snowy owl, despite some overlap in size with both other species. It is sometimes referred to as the world's largest owl,〔〔(【引用サイトリンク】title=Eurasian Eagle-Owl )〕 although Blakiston's fish owl (''B. blakistoni'') is slightly heavier on average and the much lighter weight great grey owl (''Strix nebulosa'') is slightly longer on average.〔〔(【引用サイトリンク】title=Blakiston’s Fish Owl Project )〕 It should be noted, however, that Heimo Mikkola reported the largest specimens of eagle-owl as having the same upper body mass, , as the largest Blakiston’s fish owl and attained a length of around longer.〔 In terms of average weight and wing size, the Blakiston’s is the slightly larger species seemingly, even averaging a bit larger in these aspects than the biggest eagle-owl races from Russia.〔〔 Also, although shorter than the largest of the latter species, the Eurasian eagle-owl can weigh well more than twice as much as the largest great grey owl.〔〔Bull, Evelyn L. and James R. Duncan. 1993. "Great Gray Owl (Strix nebulosa)", The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology.〕 The Eurasian eagle-owl typically has a wingspan of ,〔 with the largest specimens possibly attaining .〔Schuchmann (1999). Eurasian Eagle Owl (Bubo bubo). pp. 186 in: del Hoyo, Elliott & Sargatal, eds (1999). ''Handbook of the Birds of the World''. Vol. 5. Lynx Edicions, Barcelona. ISBN 84-87334-25-3〕〔''Animal Records'' by Mark Carwadine. Sterling (2008), ISBN 1402756232〕 The total length of the species can vary from .〔〔〔Grimmett, R., Roberts, T. J., Inskipp, T., & Byers, C. (2008). ''Birds of Pakistan''. A&C Black.〕 Females can weigh from and males can weigh from .〔〔Alonso, R. 2009. ''Datado y sexado de las Estrigiformes Ibericas: Buho Real Eurasian Eagle Owl Bubo bubo''.〕 In comparison, the barn owl (''Tyto alba''), the world's most widely distributed owl species, weighs about 500 g (1.1 lb) and the great horned owl (''Bubo virginianus''), which fills the eagle-owl's ecological niche in North America, weighs around 1.4 kg (3.1 lb).〔''CRC Handbook of Avian Body Masses'' by John B. Dunning Jr. (Editor). CRC Press (1992), ISBN 978-0-8493-4258-5.〕 Besides the female being larger, there is little external sexual dimorphism in the Eurasian eagle-owl although the ear tufts of males reportedly tend to be more upright than those of females.〔 When an eagle-owl is seen on its own in the field, it is generally not possible to distinguish the individual’s sex. However, gender determination by size is possible via in hand measurements.〔del Mar Delgado, M., & Penteriani, V. (2004). ''Gender determination of Eurasian Eagle-Owls (Bubo bubo) by morphology''. Journal of Raptor Research, 38, 375-377.〕 Reportedly, in some populations the female may be slightly darker on average than the male.〔 The plumage coloration across at least 13 accepted subspecies can be highly variable. The upper parts may be brown-black to tawny-buff to pale creamy gray, typically showing dense freckling on the forehead and crown, stripes on the nape, sides and back of the neck, and dark splotches on the pale ground colour of the back, mantle and scapulars. A narrow buff band, freckled with brown or buff, often runs up from the base of the bill, above the inner part of the eye and along the inner edge of the black-brown ear tufts. The rump and upper tail-coverts are delicately patterned with dark vermiculations and fine wavy barring, the extent of which varies with subspecies. The underwing coverts and undertail coverts are similar but tend to be more strongly barred in brownish-black.〔 The primaries and secondaries are brown with broad dark brown bars and dark brown tips, and grey or buff irregular lines. A complete moult takes place each year between July and December.〔 The facial disc is tawny-buff, speckled with black-brown, so densely on the outer edge of the disc as to form a "frame" around the face. The chin and throat are white with a brownish central streak. The feathers of the upper breast generally have brownish-black centres and reddish-brown edges except for the central ones which have white edges. The chin and throat may appear white continuing down the center of the upper breast. The lower breast and belly feathers are creamy-brown to tawny buff to off-white with a variable amount of fine dark wavy barring, on a tawny-buff ground colour. The legs and feet (which are feathered almost to the talons) are likewise marked on a buff ground colour but more faintly. The tail is tawny-buff, mottled dark grey-brown with about six black-brown bars. The bill and feet are black. The iris is most often orange but is fairly variable. In some European birds, the iris is a bright reddish, blood-orange colour but then in subspecies found in arid, desert-like habitats, the iris can range into an orangish-yellow colour (most closely related species generally have yellowish-coloured irises, excluding their Indian cousins).〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Eurasian eagle-owl」の詳細全文を読む スポンサード リンク
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