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Wednesday, 16 December 2020

16-12-2020 SUECA, VALENCIA - COMMON BUZZARD (Buteo buteo)


The common buzzard (Buteo buteo) is a medium-to-large bird of prey which has a large range. It is a member of the genus Buteo in the family Accipitridae. The species lives in most of Europe and extends its breeding range across much of the Palearctic as far as northwestern China (Tian Shan), far western Siberia and northwestern Mongolia. Over much of its range, it is a year-round resident. However, buzzards from the colder parts of the Northern Hemisphere as well as those that breed in the eastern part of their range typically migrate south for the northern winter, many journeying as far as South Africa.

The common buzzard is an opportunistic predator that can take a wide variety of prey, but it feeds mostly on small mammals, especially rodents such as voles. It typically hunts from a perch. Like most accipitrid birds of prey, it builds a nest, typically in trees in this species, and is a devoted parent to a relatively small brood of young. The common buzzard appears to be the most common diurnal raptor in Europe, as estimates of its total global population run well into the millions.


The common buzzard is a medium to large sized raptor that is highly variable in plumage. Most buzzards are distinctly round headed with a somewhat slender bill, relatively long wings that either reach or fall slightly short of the tail tip when perched, a fairly short tail, and somewhat short and mainly bare tarsi. They can appear fairly compact in overall appearance but may also appear large relative to other more common raptorial birds such as kestrels and sparrowhawks.The common buzzard measures between 40 and 58 cm (1 ft 4 in and 1 ft 11 in) in length with a 109–140 cm (3 ft 7 in – 4 ft 7 in) wingspan. Females average about 2–7% larger than males linearly and weigh about 15% more. Body mass can show considerable variation. Buzzards from Great Britain alone can vary from 427 to 1,183 g (15 oz to 2 lb 10 oz) in males, while females there can range from 486 to 1,370 g (1 lb 1 oz to 3 lb 0 oz).


In Europe, most typical buzzards are dark brown above and on the upperside of the head and mantle, but can become paler and warmer brown with worn plumage. The flight feathers on perched European buzzards are always brown in the nominate subspecies (B. b. buteo). Usually the tail will usually be narrowly barred grey-brown and dark brown with a pale tip and a broad dark subterminal band but the tail in palest birds can show a varying amount a white and reduced subterminal band or even appear almost all white. In European buzzards, the underside coloring can be variable but most typically show a brown-streaked white throat with a somewhat darker chest. A pale U across breast is often present; followed by a pale line running down the belly which separates the dark areas on breast-side and flanks. These pale areas tend to have highly variable markings that tend to form irregular bars. Juvenile buzzards are quite similar to adult in the nominate race, being best told apart by having a paler eye, a narrower subterminal band on the tail and underside markings that appear as streaks rather than bars. Furthermore, juveniles may show variable creamy to rufous fringes to upperwing coverts but these also may not be present. Seen from below in flight, buzzards in Europe typically have a dark trailing edge to the wings. If seen from above, one of the best marks is their broad dark subterminal tail band.


Flight feathers of typical European buzzards are largely greyish, the aforementioned dark wing linings at front with contrasting paler band along the median coverts. In flight, paler individuals tend to show dark carpal patches that can appears as blackish arches or commas but these may be indistinct in darker individuals or can appear light brownish or faded in paler individuals. Juvenile nominate buzzards are best told apart from adults in flight by the lack of a distinct subterminal band (instead showing fairly even barring throughout) and below by having less sharp and brownish rather than blackish trailing wing edge. Juvenile buzzards show streaking paler parts of under wing and body showing rather than barring as do adults. Beyond the typical mid-range brownish buzzard, birds in Europe can range from almost uniform black-brown above to mainly white. Extreme dark individuals may range from chocolate brown to blackish with almost no pale showing but a variable, faded U on the breast and with or without faint lighter brown throat streaks. Extreme pale birds are largely whitish with variable widely spaced streaks or arrowheads of light brown about the mid-chest and flanks and may or may not show dark feather-centres on the head, wing-coverts and sometimes all but part of mantle. Individuals can show nearly endless variation of colours and hues in between these extremes and the common buzzard is counted among the most variably plumage diurnal raptors for this reason. One study showed that this variation may actually be the result of diminished single-locus genetic diversity.


Common buzzard often inhabit the interface of woods and open areas.
The common buzzard is found throughout several islands in the eastern Atlantic islands, including the Canary Islands and Azores and almost throughout Europe. It is today found in Ireland and in nearly every part of Scotland, Wales and England. In mainland Europe, remarkably, there are no substantial gaps without breeding common buzzards from Portugal and Spain to Greece, Estonia, Belarus and Ukraine, though are present mainly only in the breeding season in much of the eastern half of the latter three countries. They are also present in all larger Mediterranean islands such as Corsica, Sardinia, Sicily and Crete. Further north in Scandinavia, they are found mainly in southeastern Norway (though also some points in southwestern Norway close to the coast and one section north of Trondheim), just over the southern half of Sweden and hugging over the Gulf of Bothnia to Finland where they live as a breeding species over nearly two-thirds of the land.


The common buzzard reaches its northern limits as a breeder in far eastern Finland and over the border to European Russia, continuing as a breeder over to the narrowest straits of the White Sea and nearly to the Kola Peninsula. In these northern quarters, the common buzzard is present typically only in summer but is a year-around resident of a hearty bit of southern Sweden and some of southern Norway. Outside of Europe, it is a resident of northern Turkey (largely close to the Black Sea) otherwise occurring mainly as a passage migrant or winter visitor in the remainder of Turkey, Georgia, sporadically but not rarely in Azerbaijan and Armenia, northern Iran (largely hugging the Caspian Sea) to northern Turkmenistan. Further north though its absent from either side of the northern Caspian Sea, the common buzzard is found in much of western Russia (though exclusively as a breeder) including all of the Central Federal District and the Volga Federal District, all but the northernmost parts of the Northwestern and Ural Federal Districts and nearly the southern half of the Siberian Federal District, its farthest easterly occurrence as a breeder. It also found in northern Kazakhstan, Kyrgyzstan, far northwestern China (Tien Shan) and northwestern Mongolia.


The common buzzard generally inhabits the interface of woodlands and open grounds; most typically the species lives in forest edge, small woods or shelterbelts with adjacent grassland, arables or other farmland. It acquits to open moorland as long as there is some trees for perch hunting and nesting use. The woods they inhabit may be coniferous, temperate broadleaf and mixed forests and temperate deciduous forest with occasional preferences for the local dominant tree. It is absent from treeless tundra, as well as the Subarctic where the species almost entirely gives way to the rough-legged buzzard. The common buzzard is sporadic or rare in treeless steppe but can occasionally migrate through it (despite its name, the steppe buzzard subspecies breeds primarily in the wooded fringes of the steppe). The species may be found to some extent in both in mountainous or flat country. Although adaptable to and sometimes seen in wetlands and in coastal areas, buzzards are often considered more of an upland species and neither appear to be regularly attracted to or to strongly avoid bodies of waters in non-migratory times.


Buzzards spend much of their day perched.
The common buzzard is a typical Buteo in much of its behaviour. It is most often seen either soaring at varying heights or perched prominently on tree tops, bare branches, telegraph poles, fence posts, rocks or ledges, or alternately well inside tree canopies. Buzzards will also stand and forage on the ground. In resident populations, it may spend more than half of its day inactively perched. Furthermore, it has been described a "sluggish and not very bold" bird of prey. It is a gifted soarer once aloft and can do so for extended periods but can appear laborious and heavy in level flight, more so nominate buzzards than steppe buzzards. Particularly in migration, as was recorded in the case of steppe buzzards' movement over Israel, buzzards readily adjust their direction, tail and wing placement and flying height to adjust for the surrounding environment and wind conditions. In Israel, migrant buzzards rarely soar all that high (maximum 1,000–2,000 m (3,300–6,600 ft) above ground) due to the lack of mountain ridges that in other areas typically produce flyways; however tail-winds are significant and allow birds to cover a mean of 9.8 m/s (35 km/h; 22 mph; 32 ft/s).