The Eurasian eagle-owl was
formally described by the Swedish naturalist
Carl Linnaeus in 1758 in the
tenth edition of his
Systema Naturae under the
binomial name Strix bulbo. Although Linnaeus specified the "habitat" as "Europa" the
type locality is restricted to Sweden. The Eurasian eagle-owl is now placed in the
genus Bubo that was introduced by
André Duméril in 1805. The genus
Bubo with about 10 extant species includes many of the larger owl species in the world today. Based on an extensive fossil record and a central distribution of extant species on that continent,
Bubo appears to have evolved into existence in Africa, although early radiations seem to branch from southern Asia, as well. Addirionally, while some authors have considered
fishing owls as possibly inclusive with
Bubo, they are also distinct and belong in the genus
Scotopelia. The
Pharaoh eagle-owl, distributed in the
Arabian Peninsula and sections of the
Sahara Desert through
North Africa where rocky outcrops are found, was until recently considered a subspecies of the Eurasian eagle-owl. The Pharaoh eagle-owl apparently differs about 3.8% in
mitochondrial DNA from the Eurasian eagle-owl, well past the minimum genetic difference to differentiate species of 1.5%. The Indian eagle-owl (
B. bengalensis) was also considered a subspecies of the Eurasian eagle-owl until recently, but its smaller size, distinct voice (more clipped and high-pitched than the Eurasian), and the fact that it is largely
allopatric in distribution (filling out the
Indian subcontinent) with other Eurasian eagle-owl races has led to it being considered a distinct species. The mitochondrial DNA of the Indian species also appears considerably distinct from the Eurasian species. The fourth and most famous derivation of the evolutionary line that includes the Eurasian eagle-owl is the
great horned owl, which appears to have been the result of primitive eagle-owls spreading into North America. According to some authorities, the great horned owls and Eurasian eagle-owls are barely distinct as species, with a similar level of divergence in their plumages as the Eurasian and North American representations of the great grey owl or the long-eared owl. Eurasian eagle-owls in captivity have produced apparently healthy hybrids with both the Indian eagle-owl and the great horned owl.
Subspecies ,
B. b. turcomanus , Germany ,
B. b. hemachalana •
B. b. hispanus (Rothschild and Hartert, 1910) – Also known as the
Spanish eagle-owl or the
Iberian eagle-owl. This subspecies mainly occurs on the
Iberian Peninsula, where it occupies a majority of Spain and scattered spots in Portugal. The Spanish eagle-owl is the most similar in plumage to the nominate subspecies amongst other subspecies, but tends to be a somewhat lighter, more greyish colour, with generally lighter streaking and a paler belly. In males, wing chord length can range from and in females from . Wingspans in this subspecies can vary from , averaging about . Among standard measurements of
B. b. hispanus, the
tail is , the total bill length is and the
tarsus is . Adult male
B. b. hispanus from Spain weigh , averaging , while females weigh from , averaging . the nominate subspecies inhabits continental Europe from near the
Arctic Circle in Norway, Sweden, Finland, the southern
Kola Peninsula, and
Arkhangelsk where it ranges north to about latitude 64° 30' N., southward to the
Baltic Sea, central Germany, to southeastern Belgium, eastern, central, and southern France to Northern Spain and parts of Italy including
Sicily, and through Central and
Southeastern Europe to
Greece. It intergrades with
B. b. ruthenus in northern Russia around the basin of the upper
Mezen River and in the eastern vicinity of
Gorki Leninskiye,
Tambov and
Voronezh, and intergrades with
B. b. interpositus in northern Ukraine. This is a medium-sized race, measuring in wing chord length in males and . The total bill length is . Another set of Finnish eagle-owls averaged somewhat larger still, with males averaging and females averaging . The subspecies seems to follow
Bergmann's rule in regards to body size decreasing closer to the
Equator, as specimens from
central Europe average in body mass and those from Italy average about . The weight range for eagle-owls in Italy is . The nominate subspecies is perhaps the darkest of eagle-owl subspecies. Many nominate birds are heavily overlaid with broad black streaking over the upper-parts, head and chest. While generally a brownish base-colour, many nominate owls can appear rich rufous, especially about the head, upper-back and wing primaries. The lower belly is usually a buff brown, as opposed to whitish or yellowish in several other subspecies. This subspecies replaces the nominate in eastern Russia from about latitude 660 N. in the
Timan-Pechora Basin south to the western
Ural Mountains and the upper
Don and lower
Volga Rivers.
B. b. interpositus ranges from southern Russia, south of the nominate, with which it intergrades in northern
Ukraine, from
Bessarabia and the steppes of
Ukraine north to
Kyiv and
Kharkiv then eastward to the
Crimea, the
Caucasus and
Transcaucasia to northwestern and northern Iran (
Elburz, region of
Tehran, and probably the southern
Caspian districts), and through
Asia Minor south to
Syria and
Iraq but not to the
Syrian desert where it is replaced by the pharaoh eagle-owl. The latter and
B. b. interpositus reportedly hybridize from western
Syria south to southern
Palestine. This subspecies is distributed from the
Ural Mountains of western
Siberia and
Bashkiria to the mid
Ob River and the western
Altai Mountains, north to limits of the taiga, the most northerly distribution known in the species overall. This subspecies is physically the most distinctive of all the Eurasian eagle-owls, and is sometimes considered the most "beautiful and striking". This subspecies is found in central Siberia from about the
Ob eastward to
Lake Baikal, north to about latitudes 580 to 590 N on the
Yenisei River, south to the
Altai,
Tarbagatai and the
Saur Mountain ranges and in
Tannu Tuva and
Khangai Mountains in northwestern
Mongolia, grading into
B. b. sibiricus near
Tomsk in the west and into
B. b. ussuriensis in the east of northern Mongolia. The zone of intergradations with the latter in Mongolia seems to be quite extensive, with intermediate eagle-owls being especially prevalent around the
Tuul River Valley, resulting in owls intermediate in coloration between
B. b. yenisseensis and
B. b. ussuriensis. •
B. b. ussuriensis (Poljakov, 1915) – Would presumably be also known as the
Ussuri eagle-owl. This subspecies ranges from southeastern Siberia, to the south of the range of
B. b. jakutensis, southward through eastern
Transbaikal,
Amurland,
Sakhalin,
Ussuriland and the
Manchurian portion of the
Chinese provinces of
Shaanxi,
Shanxi and
Hebei. Going on wing chord length,
B. b. ussuriensis is slightly smaller than the various subspecies from further north in Siberia. Males have a wing chord length of and females are . It is distributed from
Kazakhstan between the
Volga and upper
Ural Rivers, the
Caspian Sea coast and the former
Aral Sea, but replaced in that country by
B. b. omissus in the mountainous south and in the coastal region of the
Mangyshlak Peninsula by
B. b. gladkovi. Out of Kazakhstan, the range of
B. b. turcomanus continues through the
Transbaikal and the
Tarim Basin to western
Mongolia. The plumage background colour is pale, yellowish-buff. The dark patterns on the upper- and underparts is paler, less well-defined and more shattered than in
B. b. interpositus. Dark longitudinal patterning on the under-parts discontinue above the belly.
B. b. turcomanus is greyer than
B. b. hemalachanus but is otherwise somewhat similar-looking. This subspecies is unique in that it seems to shun mountainous and obvious rocky habitats in favor of low hills, plateaus, lowlands, steppes, and semideserts at or near sea-level.
B. b. omissus is native to
Turkmenistan and adjacent regions of northeastern Iran and western
Xinjiang. The range of
B. b. nikolskii appears to extend from the
Balkan Mountains and
Kopet Dagh in southern
Transcaspia eastward to southeastern
Uzbekistan or to perhaps southwestern
Tadzhikistan, then southward 290 N. It may range north to
Iran,
Afghanistan and
Baluchistan south to the region of
Kalat, or at about latitude of
Hindu Kush. In Iran,
B. b. nikolskii is replaced by
B. b. interpositus in the north, and probably also in the northwest, and probably by
B. b. hemalachana in
Badakhshan, part of northeastern Afghanistan. The birds of southern
Tadzhikistan found west of the
Pamirs are more or less intermediate between
B. b. omissus and
B. b. hemachalana. The range of
B. b. hemachalana extends from the
Himalayas, from
Pakistan through
Jammu and Kashmir and
Ladakh to at least
Bhutan, also living in
Tibet. Its range continues also westward to the
Tian Shan system in
Russian Turkestan, west to the
Karatau, north to the
Dzungarian Alatau, east to at least the
Tekkes Valley in
Xinjiang, and south to the regions of
Kashgar,
Yarkant and probably the western
Kunlun Mountains. This bird is partly migratory, descending to the plains of
Turkmenistan with colder winter weather, and apparently reaches northern
Balochistan. This subspecies is physically similar to
B. b. turcomanus but the background colour is more light yellowish-brown and less buff. The dark patterns on the upperparts and underparts are more expressed and less regular than in
B. b. turcomanus and
B. b. omissus and the general colour from the mantle to the ear tufts is a more consistent brownish colour than most other abutting races.
B. b. hemachalana differs from
B. b. yenisseensis by being much more yellow on the rump, under tail coverts, and outer tail feathers, rather than grayish or whitish, and the ground coloration of its body is more yellowish above, and is less whitish below. Dark longitudinal pattern on the under-parts cover the forebelly.
B. b. kiautschensis is much darker, more tawny and rufous, and slightly smaller than
B. b. ussuriensis. According to museum accounts, it resembles the nominate subspecies from Europe (though obviously considerably disparate in distribution) rather closely in coloration but differs from it by being paler, more mottled, and less heavily marked with brown on the upper parts, by having narrower dark shaft streaks on the under parts, which average also duller and more ocher, and by averaging smaller. •
B. b. swinhoei (Hartert, 1913) – This subspecies could be also known as the
South Chinese eagle-owl. It is endemic to southeastern China. A quite rufescent form, it is somewhat similar to
B. b. kiautschensis. In this smallish subspecies, the wing chord measures in both sexes. This is a rather poorly known and described subspecies and is considered invalid by some authorities. ==Habitat==