Utente:BlackPanther2013/Sandbox/rapaci: differenze tra le versioni
Contenuto cancellato Contenuto aggiunto
Nessun oggetto della modifica |
|||
Riga 50:
L''''otarda kori''' ('''''Ardeotis kori''''' <span style="font-variant: small-caps">([[William John Burchell|Burchell]], [[1822]])</span>) è un [[Aves|uccello]] della [[Famiglia (tassonomia)|famiglia]] degli [[Otididae|Otididi]] originario dell'[[Africa orientale]] e [[Africa del Sud|meridionale]]<ref name=IOC>{{IOC|titolo=Family Otididae|url=https://www.worldbirdnames.org/bow/bustards/|accesso=12 ottobre 2018}}</ref>.
==Taxonomy==▼
English naturalist [[William John Burchell]] described the kori bustard in 1822. The specific epithet ''kori'' is derived from the [[Tswana language|Tswana]] name for this bird - ''Kgori''.<ref name= Williams/>▼
Two subspecies are currently recognized:▼
*''Ardeotis kori kori'' – the relatively pale nominate race from [[Botswana]], [[Zimbabwe]], [[Namibia]], southern [[Angola]], [[South Africa]] and [[Mozambique]].<ref name= Johnsgard/>▼
*''Ardeotis kori struthiunculus'' – the "Somali kori" distributed in [[Ethiopia]], [[Uganda]], [[South Sudan]], [[Kenya]] and [[Tanzania]]. The two races are separated by the miombo woodlands of central Africa.<ref name="HBW">{{cite book |title=[[Handbook of the Birds of the World]] |last1=del Hoyo |first1=J | last2=Elliot | first2 = A | last3=Sargatal | first3 = J | year=1996 |publisher=[[Lynx Edicions]] |___location=[[Barcelona]] |isbn=84-87334-20-2|volume=3}}</ref> This race has a more boldly patterned head and slightly more black and white patterning on the wings. The two races are similar in size, though ''A. k. struthiunculus'' may be slightly larger. This may be a distinct species.<ref name= Sinclair/>▼
== Descrizione ==
Riga 69 ⟶ 62:
Le dimensioni e la cresta scura rendono facilmente distinguibile l'otarda kori dalle altre specie di otarde con le quali condivide l'areale<ref name=Sasol>I. Sinclair, P. Hockey e W. Tarboton (1997). ''Sasol Birds of Southern Africa''. Struik Publishers (Pty) Ltd., Città del Capo.</ref>. Tuttavia, l'[[Africa orientale]] ospita la maggiore diversità tra le otarde, comprese specie di dimensioni piuttosto considerevoli, e questo potrebbe causare un po' di confusione. L'otarda kori si differenzia dall'otarda di Stanley (''[[Neotis denhami]]'') e dall'otarda di Ludwig (''[[Neotis ludwigii]]''), con le quali talvolta viene vista alimentarsi insieme, per la colorazione più grigia del piumaggio e per la mancanza di una zona di colore rosso fulvo sulla parte posteriore del collo e su quella alta della mantellina. In volo è distinguibile da queste due specie più piccole per il fatto di non presentare nessun segno bianco sulla parte superiore dell'ala, che è uniformemente grigia. Sia l'otarda di Stanley che quella di Ludwig, inoltre, sono prive della caratteristica cresta scura dell'otarda kori<ref name=Williams/><ref name=Ginn/><ref name=Sasol/>. Più simile all'otarda kori, e quasi delle stesse dimensioni, è l'otarda d'Arabia (''[[Ardeotis arabs]]''), sua stretta parente, che, nonostante il nome, è presente anche in alcune regioni dell'[[Africa orientale]]. Tuttavia, quest'ultima presenta copritrici alari dalle punte bianche, dorso di colore più brunastro e vermicolature sul collo molto fini; inoltre, non possiede la base nera del collo e il nero delle copritrici alari presenti nell'otarda kori<ref name=Williams/><ref name=Sinclair/>.
[[File:Ardeotis kori portrait.jpg|thumb|left|
==Distribution and habitat==▼
[[File:Koribustard.jpg|thumb|left|''A. k. struthiunculus'' in [[Amboseli]], [[Kenya]]]]▼
The kori bustard is found throughout southern Africa, except in densely wooded areas. They are common in [[Botswana]] and [[Namibia]], extending into southern [[Angola]] and marginally into southwestern [[Zambia]]. In [[Zimbabwe]] they are generally sparse but locally common, particularly on the central plateau. Their distribution range extends along the [[Limpopo River]] valley into southern [[Mozambique]] and the eastern lowveld of [[South Africa]]. In South Africa they are also infrequent to rare in the [[Free State (province)|Free State]], [[North West (South African province)|North West]] and [[Northern Cape|Northern Cape Province]]s, extending southwards into the interior of the [[Western Cape|Western]] and [[Eastern Cape|Eastern Cape Provinces]]. Kori bustards are absent from the coastal lowlands along the south and east of South Africa and from high mountainous areas. This species is common in [[Tanzania]] at [[Ngorongoro National Park]], [[Kitulo National Park]] and [[Serengeti National Park]]. A geographically disjunct population also occurs in the deserts and savanna of northeastern Africa. Here, the species ranges from extreme southeast [[South Sudan]], north [[Somalia]], [[Ethiopia]] through all of [[Kenya]] (except coastal regions), [[Tanzania]] and [[Uganda]].<ref name= Sinclair>Sinclair I. & Ryan P. 2003. ''A comprehensive illustrated field guide : Birds of Africa south of the Sahara''. Struik Publishers, Cape Town.</ref> Kenya may hold the largest population of kori bustards of any country and it can even border on abundant in the [[North Eastern Province, Kenya|North Eastern Province]].<ref name= Ginn/> They are usually residential in their range, with some random, nomadic movement following rainfall.<ref name= Ginn>Ginn P.J., McIlleron W.G. & Milstein P. le S. 1989. ''The Complete Book of southern African birds''. Struik Winchester, Cape Town.</ref>▼
== Biologia ==
This species occurs in open grassy areas, often characterized by sandy soil, especially [[Kalahari Desert|Kalahari sands]], and short grass usually near the cover of isolated clumps of trees or bushes.<ref name= Ginn/> It may be found in plains, arid plateaus, [[Highveld|highveld grassland]], arid scrub, lightly wooded savanna, open dry [[bushveld]] and semi-desert.<ref name= Maclean>Maclean, G.L. 1993. ''Robert's Birds of Southern Africa. Sixth Edition''. John Voelcker Bird Book Fund, Cape Town.</ref> Where this species occurs, annual rainfall is quite low, between {{convert|100|and|600|mm|in|abbr=on}}.<ref name= Maclean/> Breeding habitat is savanna in areas with sparse grass cover and scattered trees and shrubs. When nesting they sometimes use hilly areas.<ref name= Tarboton>Tarboton W. 2001. ''A Guide to the Nests and Eggs of Southern African Birds''. Struik Publishers (Pty) Ltd., Cape Town.</ref> They follow fires or herds of foraging ungulates, in order to pick their various foods out of the short grasses. They may also be found in cultivated areas, especially wheat fields with a few scattered trees.<ref name= Ginn/> This bustard is not found in well-wooded and forested areas due to the fact that it needs a lot of open space in which to take off.<ref name= Ginn/> In arid grassland areas it is found along dry watercourses where patches of trees offer shade during the heat of the day.<ref name= NatZoo>{{cite web |url=http://nationalzoo.si.edu/SCBI/TropicalEcosystems/KoriBustards/biology.cfm# |title=Smithsonian Conservation Biology Institute- Kori Bustard |first=Sara|last=Hallager |publisher=The Smithsonian Institution |accessdate=2013-08-30}}</ref>▼
[[File:Kori Bustard at Maasai Mara.jpg|400px|thumb|right|
▲[[File:Ardeotis kori portrait.jpg|thumb|left|A close-up of the plumage of a captive male]]
▲[[File:Kori Bustard at Maasai Mara.jpg|400px|thumb|right|Male ''A. k. struthiunculus'' at [[Maasai Mara]], [[Kenya]]]]
▲Kori bustards spend most of their time on the ground, with up to 70% of their time being on foot,<ref name= Williams/> although they do occasionally forage in low bushes and trees. There is a lone report of a bird sighted in Kenya perched at the top of a tree.<ref>L. Hudson, pers. comm</ref> This bustard is a watchful and wary bird. Their behavior varies however, and they are usually very shy, running or crouching at the first sign of danger; at other times they can be completely fearless of humans.<ref name= Williams/> They have a hesitant, slow manner of walking, and when they detect an intruder they try to escape detection by moving off quietly with the head held at an unusual angle of between 45° and 60°.<ref name= Ginn/> Being a large and heavy bird, it avoids flying if possible. When alarmed it will first run and, if pushed further, will take to the air on the run with much effort, its wings making heavy wingbeats. Once airborne it flies more easily with slow, measured wingbeats, with the neck extended and the legs folded. It usually remains low and lands again within sight.<ref name= Liversidge/> When they land, kori bustards keep their wings spread and only fold them when the bird has slowed down to a walking speed.<ref name= Ginn/> Kori bustards have no preen gland, so to keep clean, they produce a powder down. Sun bathing and dust bathing are practiced.<ref name= NatZoo/> This bird has a loud, booming [[mating call]] which is often uttered just before dawn and can be heard from far away. Mostly residential, kori bustards may engage in nomadic movements.<ref name= Sasol/> These migratory movements are probably influenced by rainfall and there is no evidence suggesting any regular pattern. These local migrations take place at night but have not been mapped. In the [[Etosha National Park]] these birds have been recorded moving up to {{convert|85|km|mi|abbr=on}} from [[mopane]] woodland to open grassland plains and returning again the following season.<ref name= Ginn/> Trial satellite tagging of one male kori bustard by the [[National Museums of Kenya]] demonstrated a migration along the [[East African Rift|Rift Valley]] between [[Tanzania]] and southeastern [[South Sudan]].<ref>Njoroge, P. and Launay, F.. 1998. ''Satellite Tracking of Kori bustards Ardeotis kori in Kenya''. Scopus 20: 19-22.</ref> Additionally, adult and juvenile males move after the breeding season, whereas females do not appear to do so.<ref name= Harrison/> Generally the kori bustard feeds during the morning and in the evening, spending the rest of the day standing still in any available shade.<ref name= Ginn/>
===Voice===
Riga 111 ⟶ 98:
Being a large, ground-dwelling bird species, the kori bustard is vulnerable to many of Africa's myriad of formidable terrestrial predators. [[Leopard]]s (''Panthera pardus''), [[caracal]]s (''Caracal caracal''), [[cheetah]]s (''Acinonyx jubatus''), [[lion]]s (''Panthera leo''), [[spotted hyena]] (''Crocuta crocuta''), [[Python sebae|African rock pythons]] (''Python sebae''), [[jackal]]s (''Canis'' spp.), [[Verreaux's eagle]] (''Aquila verreauxii''), [[martial eagle]]s (''Polemaetus bellicosus''), and [[Verreaux's eagle-owl]]s (''Bubo lacteus'') are amongst their potential natural predators. Additionally, [[warthog]]s (''Phacochoerus spp.''), [[tawny eagle]]s (''Aquila rapax''), [[Cape eagle-owl]]s (''Bubo capensis''), [[mongoose]]s and [[baboon]]s (''Papio'' spp.) may eat eggs, small chicks, and in the case of the tawny eagle and the Cape eagle-owl sometimes adults.<ref name= Ginn/><ref name= NatZoo/><ref name= Hallager/> When alarmed, kori bustards make barking calls and bend forward and spread their tail and wings to appear larger.<ref name= NatZoo/> Adults will growl when their young are threatened by predators.<ref name= Harrison/> Chicks tend to be the most vulnerable to predators by far. Many, despite their cryptic camouflage and the mother's defenses, are regularly picked off by jackals and leopards at night.<ref name= Ginn/> Up to 82% of kori bustard chicks die in their first year of life.<ref name= Osborne/> When found with carmine bee-eaters, the smaller birds may incidentally provide some protection from predators due to their vigilance.<ref>Jackson, T.H.E.. 1945. ''Some Merops-Ardeotis Perching Associations in Northern Kenya''. Ibis 87: 284-286.</ref> The display of the adult male may make it more conspicuous to larger predators, such as hyenas or lions.<ref name= Tarboton/> A shock display may be performed when a bird is alarmed. While too large to be prey for most predatory birds, it is known that the martial eagle is a serious natural enemy even for adult bustards. In one documented attack by a martial eagle on an adult kori bustard, both birds ended up wounded, the eagle with a bleeding leg from the bustard's counterattack, but the bustard more seriously injured, with a broken wing and several open wounds. Although it walked away, the injured bustard in the confrontation was found dead the next morning, being fed on by a jackal.<ref>{{cite web |url=http://www.birdforum.net/showthread.php?t=180293 |title=Martial Eagle Attack a Kori Bustard in South Africa |publisher=BirdForum |accessdate=2013-07-26}}</ref>
▲==Distribution and habitat==
▲[[File:Koribustard.jpg|thumb|left|''A. k. struthiunculus'' in [[Amboseli]], [[Kenya]]]]
▲The kori bustard is found throughout southern Africa, except in densely wooded areas. They are common in [[Botswana]] and [[Namibia]], extending into southern [[Angola]] and marginally into southwestern [[Zambia]]. In [[Zimbabwe]] they are generally sparse but locally common, particularly on the central plateau. Their distribution range extends along the [[Limpopo River]] valley into southern [[Mozambique]] and the eastern lowveld of [[South Africa]]. In South Africa they are also infrequent to rare in the [[Free State (province)|Free State]], [[North West (South African province)|North West]] and [[Northern Cape|Northern Cape Province]]s, extending southwards into the interior of the [[Western Cape|Western]] and [[Eastern Cape|Eastern Cape Provinces]]. Kori bustards are absent from the coastal lowlands along the south and east of South Africa and from high mountainous areas. This species is common in [[Tanzania]] at [[Ngorongoro National Park]], [[Kitulo National Park]] and [[Serengeti National Park]]. A geographically disjunct population also occurs in the deserts and savanna of northeastern Africa. Here, the species ranges from extreme southeast [[South Sudan]], north [[Somalia]], [[Ethiopia]] through all of [[Kenya]] (except coastal regions), [[Tanzania]] and [[Uganda]].<ref name= Sinclair>Sinclair I. & Ryan P. 2003. ''A comprehensive illustrated field guide : Birds of Africa south of the Sahara''. Struik Publishers, Cape Town.</ref> Kenya may hold the largest population of kori bustards of any country and it can even border on abundant in the [[North Eastern Province, Kenya|North Eastern Province]].<ref name= Ginn/> They are usually residential in their range, with some random, nomadic movement following rainfall.<ref name= Ginn>Ginn P.J., McIlleron W.G. & Milstein P. le S. 1989. ''The Complete Book of southern African birds''. Struik Winchester, Cape Town.</ref>
▲This species occurs in open grassy areas, often characterized by sandy soil, especially [[Kalahari Desert|Kalahari sands]], and short grass usually near the cover of isolated clumps of trees or bushes.<ref name= Ginn/> It may be found in plains, arid plateaus, [[Highveld|highveld grassland]], arid scrub, lightly wooded savanna, open dry [[bushveld]] and semi-desert.<ref name= Maclean>Maclean, G.L. 1993. ''Robert's Birds of Southern Africa. Sixth Edition''. John Voelcker Bird Book Fund, Cape Town.</ref> Where this species occurs, annual rainfall is quite low, between {{convert|100|and|600|mm|in|abbr=on}}.<ref name= Maclean/> Breeding habitat is savanna in areas with sparse grass cover and scattered trees and shrubs. When nesting they sometimes use hilly areas.<ref name= Tarboton>Tarboton W. 2001. ''A Guide to the Nests and Eggs of Southern African Birds''. Struik Publishers (Pty) Ltd., Cape Town.</ref> They follow fires or herds of foraging ungulates, in order to pick their various foods out of the short grasses. They may also be found in cultivated areas, especially wheat fields with a few scattered trees.<ref name= Ginn/> This bustard is not found in well-wooded and forested areas due to the fact that it needs a lot of open space in which to take off.<ref name= Ginn/> In arid grassland areas it is found along dry watercourses where patches of trees offer shade during the heat of the day.<ref name= NatZoo>{{cite web |url=http://nationalzoo.si.edu/SCBI/TropicalEcosystems/KoriBustards/biology.cfm# |title=Smithsonian Conservation Biology Institute- Kori Bustard |first=Sara|last=Hallager |publisher=The Smithsonian Institution |accessdate=2013-08-30}}</ref>
▲==Taxonomy==
▲English naturalist [[William John Burchell]] described the kori bustard in 1822. The specific epithet ''kori'' is derived from the [[Tswana language|Tswana]] name for this bird - ''Kgori''.<ref name= Williams/>
▲Two subspecies are currently recognized:
▲*''Ardeotis kori kori'' – the relatively pale nominate race from [[Botswana]], [[Zimbabwe]], [[Namibia]], southern [[Angola]], [[South Africa]] and [[Mozambique]].<ref name= Johnsgard/>
▲*''Ardeotis kori struthiunculus'' – the "Somali kori" distributed in [[Ethiopia]], [[Uganda]], [[South Sudan]], [[Kenya]] and [[Tanzania]]. The two races are separated by the miombo woodlands of central Africa.<ref name="HBW">{{cite book |title=[[Handbook of the Birds of the World]] |last1=del Hoyo |first1=J | last2=Elliot | first2 = A | last3=Sargatal | first3 = J | year=1996 |publisher=[[Lynx Edicions]] |___location=[[Barcelona]] |isbn=84-87334-20-2|volume=3}}</ref> This race has a more boldly patterned head and slightly more black and white patterning on the wings. The two races are similar in size, though ''A. k. struthiunculus'' may be slightly larger. This may be a distinct species.<ref name= Sinclair/>
==Status==
| |||