Zavattariornis stresemanni Moltoni 1938

Zavattariornis stresemanni és un ocell de la família dels còrvids (Corvidae) i única espècie del gènere Zavattariornis. Habita zones arbustives i sabanes del sud d'Etiòpia.

Referències

Aderyn a rhywogaeth o adar yw Brân paith Stresemann (sy'n enw benywaidd; enw lluosog: brain paith Stresemann) a adnabyddir hefyd gyda'i enw gwyddonol Zavattariornis stresemanni; yr enw Saesneg arno yw Stresemann's bush crow. Mae'n perthyn i deulu'r Brain (Lladin: Corvidae) sydd yn urdd y Passeriformes.^[1]

Talfyrir yr enw Lladin yn aml yn Z. stresemanni, sef enw'r rhywogaeth.^[2]

Teulu

Mae'r brân paith Stresemann yn perthyn i deulu'r Brain (Lladin: Corvidae). Dyma rai o aelodau eraill y teulu:

Rhestr Wicidata:

Gweler hefyd

• Rhestr Goch yr IUCN

Cyfeiriadau

Straka etiopská (Zavattariornis stresemanni) je pták z čeledi krkavcovití (Corvidae), člen monotypického rodu Zavattariornis. Jeho hlavní stravou je hmyz. Svá hnízda si staví vysoko v korunách akácií. Hnízdo má obvykle kulovitý tvar s trubkovým vstupem shora.

Reference

1. ↑ Červený seznam IUCN 2018.1. 5. července 2018. Dostupné online. [cit. 2018-08-11]

Externí odkazy

• Obrázky, zvuky či videa k tématu Zavattariornis ve Wikimedia Commons
• Taxon Zavattariornis stresemanni ve Wikidruzích

Der Akazienhäher (Zavattariornis stresemanni), bisweilen auch als Zavattarivogel bezeichnet, ist ein in Äthiopien beheimateter Singvogel. Er gehört zur Familie der Rabenvögel (Corvidae).

Systematik

Der Akazienhäher wurde 1937 entdeckt. Edoardo Zavattari, der ehemalige Direktor des Zoologischen Institutes der Universität Rom, beobachtete ihn im April 1937 während zweier Expeditionen ins südäthiopische Buschland. Benannt wurde er nach dem deutschen Ornithologen Erwin Stresemann. 1938 wurde er vom italienischen Ornithologen Edgardo Moltoni erstmals beschrieben und in die monotypische Gattung Zavattariornis klassifiziert.

Merkmale

Die starenähnlichen Vögel erreichen eine Größe von 30 cm. Er ist in seiner gesamten Erscheinung blau-grau, ist aber zur Stirn hin fast weiß gefärbt. Die Kehle und die Brust sind cremefarben und die Schwungfedern sowie der Schwanz glänzend schwarz. Die Federspitzen sind bräunlich aufgehellt. Männchen und Weibchen ähneln sich, die Jungvögel sind etwas schmutziger gefärbt. Die Iris ist braun und die Augen sind von einem hellblauen Band aus nackter Gesichtshaut umgeben. Der Schnabel, die Füße und die Beine sind schwarz.

Verbreitung und Lebensraum

Sein Vorkommen ist auf Dorn-, Kurzgras- und Akaziensavannen im südlichen Äthiopien in der Nähe der Orte Yabello (Jabello), Mega and Arero beschränkt.

Lebensweise und Fortpflanzung

Außerhalb der Brutsaison ist er sehr gesellig. Sie halten sich dann gerne in Gesellschaft der Weißscheitelstare (Spreo albicapillus) auf und bilden Gruppen von vier bis zehn Vögeln. Ihre Nahrung besteht aus Insekten. Die Brutzeit ist von Februar/März bis Mai/Juni und die Nester werden in einer Höhe von 6 m in Akazienbüsche gebaut. Das Gelege besteht in der Regel aus fünf bis sechs cremefarbenen Eiern mit fliederfarbenen Flecken. Das Nest ist kugelförmig mit einem röhrenförmigen Eingang an der Oberseite. Aufgrund der langen Brutperiode ist es möglich, dass mehrere Brutpaare das Nest besuchen und dass Jungvögel aus vergangenen Brutperioden bei der Jungenaufzucht helfen.

Literatur

• Edgardo Moltoni: La posizione sistematica del genere Zavattariornis, S. A. Rev. Ital. Ornit. Anno XIX, Ser. II, 1949 (ital.)
• Mellanby, R. J., Ross, B., Watt, A., Wondafrash, M., Ewnetu, M., Broadhurst, C., Critchlow, R., Dadesa, A., Deas, T., Enawgaw, C., Gebremedin, B., Graham, E., Maclean, S., Mckean, M., Collar, N. J. & Spottiswoode, C. N. (2008): Distribution, abundance and habitat preferences of White-tailed Swallow Hirundo megaensis and Ethiopian Bush-crow Zavattariornis stresemanni, two southern Ethiopian endemics. In: Bird Conservation International 18:S. 395-412

Weblinks

– Sammlung von Bildern, Videos und Audiodateien

• Videos, Fotos und Tonaufnahmen zu Zavattariornis stresemanni in der Internet Bird Collection
• ARKive - Fotos und Informationen über Zavattariornis stresemanni (Memento vom 5. Februar 2019 im Internet Archive).
• BirdLife Species factsheet
• Zavattariornis stresemanni in der Roten Liste gefährdeter Arten der IUCN 2013.1. Eingestellt von: 2012, 2012. Abgerufen am 4. September 2013.

Stresemann's bushcrow (Zavattariornis stresemanni), also known as the Abyssinian pie, bush crow, Ethiopian bushcrow, or by its generic name Zavattariornis, is a rather starling-like bird, which is a member of the crow family, Corvidae. It is slightly larger than the North American blue jay and is a bluish-grey in overall colour which becomes almost white on the forehead. The throat and chest are creamy-white with the tail and wings a glossy black. The black feathers have a tendency to bleach to brown at their tips. The iris of the bird is brown and the eye is surrounded by a band of naked bright blue skin. The bill, legs, and feet are black.

Feeding is usually in small groups and the bird takes mainly insects. Breeding usually starts in March, with the birds building their nest high in an acacia tree. The birds usually lay five to six cream eggs with lilac blotches. The nest itself is globular in shape with a tubular entrance on top. It is possible that more than just the breeding pair visit the nest and that the young of previous years help in rearing the young.

The range of this species is quite restricted, it being confined to thorn acacia country in southern Ethiopia near Yavello (Javello), Mega, and Arero. It can be curiously absent from apparently suitable country near these areas; the reasons for this were formerly unclear, but are now thought to be related to the species requiring a "bubble" of lower temperature for proper foraging, which is only present within its small range, making it one of the few warm-blooded animals whose survival is wholly dependent on temperature (along with the sympatric white-tailed swallow). This requirement makes it extremely vulnerable to climate change, and massive declines and even potential extinction in the wild are projected in the future, making it one of the birds most threatened by climate change.^[2]

Taxonomy

Stresemann's bushcrow was formally described in 1938 by the Italian ornithologist Edgardo Moltoni.^[3] The species has been placed in several bird families since its description.^[4] It has long been considered a member of the crow family Corvidae; however, several atypical features, such as its lice being from the suborder Mallophaga, its bare facial skin being capable of movement, and the structure of its palate, have suggested that it may belong in another family.^[4] Some authors placed the species within the starling family Sturnidae due to the bushcrow's similarities in behavior and size with the wattled starling.^[4] Other authors have placed it in its own monotypic family, Zavattariornithidae.^[4] DNA-sequencing analysis supports its placement in the corvids, with its closest relatives being the ground jays, and the piapiac.^[5] It has been suggested that the bushcrow is a surviving relict ancestor to several of these relatives.^[6]

This species has numerous common names, including Stresemann's bushcrow, bush-crow, Ethiopian bushcrow, Abyssinian bushcrow, and Zavattariornis.^[4]

The genus name Zavattariornis commemorates Edoardo Zavattari, an Italian zoologist and explorer who served as the director of Rome University's Zoological Institute between 1935 and 1958.^[7] Its name commemorates Erwin Stresemann, a German ornithologist.^[8]

Description

The Stresemann's bushcrow is about 28 centimeters (11 in) long and weighs 130 grams (4.6 oz).^[4] The genders look similar and are not sexually dimorphic.^[9] Overall it is pale grey with a black tail and wings.^[4] The head, mantle, scapulars, back, rump, and uppertail coverts are all a pale grey.^[4] The feathers on the forehead, upper ear-coverts, and throat fade into white.^[4] The bright azure skin around the bushcrow's eye is featherless and can be inflated, narrowing the blackish-brown eye into a slit.^[4][9] The feathers behind the eye are capable of moving to reveal an oblong pink patch of skin.^[4] The bird's black beak decurves into a sharply pointed tip and is relatively small for a corvid.^[4][9] This beak is 33 to 39 millimeters (1.3 to 1.5 in) long.^[6] The feathers on the bird's chin are fine and can form a small tuft when erected.^[4] The bushcrow's breast and flanks are pale grey, fading into white on the rear flanks, belly, and undertail.^[9] On the wings, the lesser and median upper-wing coverts are grey, while the rest of the wing is a slightly glossy blue-black.^[4][9] Its blue-black tail is relatively long and square-ended.^[4] Its legs are black.^[9] When the plumage becomes worn, the upperparts appear to have a brownish tinge.^[6] The juvenile Stresemann's bushcrow is slightly duller than the adult, and the feathers of the body and upperwings are fringed with creamy-fawn.^[9] The facial skin, bill, and legs are also a dull grey.^[6]

The bushcrow is a very vocal species, particularly when foraging.^[9] Its main contact call has been described as a single metallic "kej".^[9] While flying, the species frequently calls out a nasal, rapid "kerr kerr kerr".^[9] While these are the most frequent vocalizations, several others are known.^[9] Allopreening adults utter a metallic "kaw, kaw, kaw".^[9] Foraging birds call out "how, how, how", a single, quiet "quak", and a soft, repeated "guw".^[9] While building its nest, the bushcrow is known to utter a low "keh" sound, and adults utter a deep "waw" while rubbing their bills together.^[9]

Distribution and habitat

This species is endemic to central-southern Ethiopia.^[10] It lives in a small area circumscribed by the towns of Yabelo, Borena, Mega, and Arero in Sidamo Province, and settles in wildlife under protection within Yabelo Wildlife Sanctuary and Borana National Park.^[6] Its total range covers about 2,400 square kilometers (930 sq mi).^[6]

The Stresemann's bushcrow lives in flat savanna covered with mature acacia and Commiphora thornbushes.^[9] The bird prefers open short-grass savannas with scattered stands of these mature thornbushes.^[9] The soil must be deep and rich to support the bushcrow.^[9] It is most numerous when these stands are next to agricultural fields.^[9] For many years it was unknown why the species could be completely absent from areas of suitable habitat near seemingly identical but inhabited land.^[6] However recent research has revealed that the bird appears to inhabit an area with a very precise average temperature extreme, all of the seemingly suitable but uninhabited surrounding lands actually have a slightly higher average temperature that appears to prevent the birds from successfully colonizing.^{[11] [12]} It is also not found near the scattered broadleaf woodland made up of Combretum and Terminalia.^[9] Its habitat is between 1,300 and 1,800 meters (4,300 and 5,900 ft) above sea level.^[9]

Ecology and behavior

The Stresemann's bushcrow is normally found in groups of about six birds.^[6] This species does not migrate.^[9]

Diet

The bushcrow feeds both on the ground and in trees.^[6] It begins foraging at sunrise.^[9] While foraging, a bushcrow can be alone, in a pair, or in a group of six or seven other bushcrows.^[9] A foraging bushcrow digs vigorously in the soil while its beak is held slightly open to catch any insects it unearths.^[9] When it catches something, it carries it to the nearest tree or bush, pins it down with its foot, and kills and eats the prey.^[9] This species has also been seen using its beak to tear apart rotten wood and inspecting cattle dung in the search for food.^[9] It may also land on the backs of cattle to search for parasites.^[9] It can also chase flying insects, which it does on foot, abruptly changing direction and taking flying leaps after its prey.^[9] It often mixes with white-crowned starlings, red-billed hornbills, red-billed buffalo weavers, and superb starlings while foraging.^[9] When hunting in the trees, it is capable of walking atop horizontal branches and jumping upwards towards the crown, then descending in a glide from the crown to the ground.^[9]

It eats primarily invertebrates and specifically insects, including termites.^[6] Larvae and pupae, especially of Coeloptera moths, are eaten as well as the adults.^[9]

Reproduction

The Stresemann's bushcrow nests either alone or in a small, loosely connected colony of three to five nests.^[9] It is monogamous and may form a lifelong pair bond.^[9] The bushcrow occasionally has a third bird, or in rare cases two to four more, help the breeding couple both build the nest and care for the young.^[9] The helpers may also not be restricted to helping one nest at a time, as they have been seen at nests across the loose colonies.^[9] Allofeeding and allopreening, where the birds feed or preen each other, takes place both between the pair and with the other bushcrows in the colony.^[9] The bushcrow lays its eggs shortly after the first rains, which normally occur in late February and early March, leading to its eggs being laid in late March and early April.^[9]

The nest is an untidy globular structure, on which the roof tapers to a point that has an opening into the interior chamber.^[6] The nest is 60 centimeters (24 in) in diameter while the interior chamber is 30 centimeters (12 in) across.^[6] To start constructing the nest, a single twig is inserted into the top of an acacia tree 5 to 6 meters (16 to 20 ft) above the ground.^[6] This leads to the paired bushcrows becoming excited, engorging their blue facial skin.^[9] Almost ritualistically the pair then pick the acacia's leaves and twigs, dropping them to the ground.^[9] The pair end this display by chasing each other through the trees before continuing construction.^[9] The nest is made out of thorny twigs while the interior chamber is lined with dry grass and dried cattle dung.^[6] Damp soil is used to keep the initial twigs connected.^[9] Old nests are repaired and reused.^[9]

Up to six eggs are laid in the nest.^[6] The bushcrow's eggs are cream-colored with pale lilac blotches that concentrate into a ring at the wider end.^[6]

Relationship with humans

Prior to modern settlement in villages, the nomadic indigenous peoples of Ethiopia provided easy hunting grounds for the bushcrow as they left loose, dung-covered soil behind as they moved their cattle.^[13] This provided a rich abundance of beetle larvae for the bushcrow to feed upon.^[13]

Conservation

Changes in the grazing habits of Ethiopia's indigenous peoples following the recent trend of settling in permanent villages have negatively impacted the Stresemann's bushcrow.^[13] While previously grazers left the soil loose and covered in dung to support the bushcrow's prey, this new lifestyle has resulted in overgrazing and soil compaction in some areas.^[13] The idea of private land ownership has also led to intensive planting of cash crops such as maize.^[9] The rich soil that the species needs to forage is also prime farming land.^[9] In the Yabello Wildlife Sanctuary, acacia trees are being collected for firewood, removing the bushcrow's nesting site.^[13] While protected under law, this sanctuary has difficulties enforcing the law.^[9] It is believed that between 1999 and 2003 the population of the bushcrow declined by 80%.^[13]

The IUCN Red List of Threatened Species lists the Stresemann's bushcrow as endangered because of its very restricted range and loss of suitable habitat. The population seems to be declining rapidly and in 2007 it was estimated that there might be fewer than 10,000 birds remaining. ^[1]

Climate change

Due to its extremely unusual and specific temperature requirements, the Stresemann's bushcrow is considered one of the most threatened birds by climate change; climate change is predicted to reduced its range by 90% by 2070 in even the best-case scenarios (occupied range can often overestimate the number of individuals occupying the range, so the estimated population reduction may be even more than 90%), dramatically increasing the risk of extinction, with worse scenarios leading to total extinction in the wild. A similar outcome is predicted for the white-tailed swallow (Hirundo megaensis), which shares the same habitat and likely similar requirements, although the estimated range reduction is much lower for the swallow. Both species may be the only examples of warm-blooded animals whose range is fully driven by the climate. Intensive conservation such as captive breeding and assisted migration may be necessary to preserve the Stresemann's bushcrow. The birds and their projected decline may be used as indicator species for climate change, allowing them to test the reliability of habitat models for other threatened animals. Both may also serve as flagship species for the impacts of climate change on avian diversity in Africa.^[2][14]

References

Cited texts

• dos Anjos, Luiz; Debus, Stephen; Madge, Steve; Marzluff, John (2009). "Family Corvidae (Crows)". In del Hoyo, Josep; Elliott, Andrew; Christie, David (eds.). Handbook of the Birds of the World. Vol. 14. Bush-shrikes to Old World Sparrows. Barcelona: Lynx Editions. ISBN 978-84-96553-50-7.
• Fry, C. Hilary; Keith, Stuart; Urban, Emil K. (2000). The Birds of Africa Volume VI. London: Academic Press. ISBN 0-12-137306-1.
• Madge, Steve; Burn, Hilary (1994). Crows and Jays: A Guide to the Crows, Jays, and Magpies of the World. Boston: Houghton Mifflin Company. ISBN 0-395-67171-X.

La Stresemana korvo (Zavattariornis stresemanni) estas granda paserina birdo de la familio de Korvedoj. Ĝi estas nomita laŭ la germana ornitologo Erwin Stresemann. Ĝi estas korvedo simila al Sturnoj sed ja el la familio de Korvedoj; spite la nomon "korvo" ĝi rilatas plie al Garoloj ol al la korvoj. Ĝi estas unu el la kvar birdospecioj kiuj estas endemismoj de Etiopio.

Aspekto

Ĝi estas iomete pli granda (ĉ 30 cm) ol la nordamerika Blua garolo, Cyanocitta cristata kaj estas helbrungriza al blugriza, pli hela en gorĝo, brusto kaj subaj partoj, dum pli helbruna en supraj partoj; vosto kaj flugiloj estas brilnigraj, kun nigraj plumoj kiuj tendencas heliĝi al bruno pinte. La iriso de tiu birdo estas bruna kaj la okulo estas ĉirkaŭita de rimarkinda nuda brilblua haŭtaĵo. La beko, gamboj kaj piedoj estas nigraj. Maskloj kaj inoj estas similaj, dum junuloj kun aspekto kvazaŭ malpureca.

Kutimoj

La teritorio de tiu afrotropisa specio estas tre limigita en dorna savano de suda Etiopio ĉirkaŭ Javello, sed ankaŭ ĉe Mega kaj Arero, proksime de la landlimo kun norda Kenjo, en savanoj kie estas malalta herbaro kaj akacioj aŭ aliaj dornaj plantoj. Ili kurioze forestas el ŝajna taŭga kamparo proksime de tiuj areoj kaj oni ne konas ties kialojn. La tuta populacio estas ĉirkaŭ 2,500-9,999 individuoj kaj malpliiĝas; la tuta teritorio estas ĉirkaŭkalkulata en 4,600 km².

Manĝado okazas kutime en etaj grupoj kiuj manĝas ĉefe insektojn.

Reproduktado okazas kutime el februaro aŭ marto al majo kaj junio, kiam la birdoj konstruas sian neston alte (ĉ 6 m) en akacio. La ino kutime demetas 5 al 6 kremokolorajn ovojn kun lilaj makulitoj. La nesto estas baloneca kun tuboforma enirejo supre. Eble ne nur la gepatroj vizitas la neston, sed eble ankaŭ aliaj paroj, dum la junuloj de antaŭaj jaroj helpas en idozorgado.

For de la periodo de reproduktado, tiuj birdoj estas tre sociaj. Ili ŝatas la akompanon de la specio de Sturnedoj nome Spreo albicapillus kaj formas grupojn de 4 al 10 individuoj.

La voĉo de tiu birdo estis priskribita kiel altatona 'ĉek'.

Aliaj

La Stresemana korvo estis malkaŝita en 1937. Edoardo Zavattari (1883-1972), eksdirektoro de la zoologia instituto de la universitato de Romo, observis ĝin en aprilo de 1937 dum du ekspedicioj al la arbustejo de suda Etiopio; el lia nomo venas la vorto por la genro. La birdo ricevis sian specifan duan nomon honore al la germana ornitologo Erwin Stresemann (1889-1972). En 1938 la specio estis priskribita la unuan fojon de la itala ornitologo Edgardo Moltoni (1896-1980) kaj estis klasita en la unuspecia genro Zavattariornis. Dekomence oni rilatigis ĝin al sturnedoj, sed la kurba beko, la naztruaj plumharoj kaj la ĉirkaŭokula haŭtaĵo identigis ĝin kiel korvedo.

Filmoligoj

• Stresemana korvo el Interreta Birdokolekto

La urraquita de Stresemann (Zavattariornis stresemanni)^[2]​ es una especie de ave paseriforme de la familia Corvidae endémica del sur de Etiopía. Es la única especie del género Zavattariornis. Es algo más grande que la urraca azul de América del Norte, aunque con un color gris azulado claro que se torna casi blanco en su frente. Su garganta y pecho son color blanquecino y sus alas y la cola son color negro lustroso. Estas plumas negras tienen los bordes pardos. Su iris es marrón y su ojo se encuentra rodeado por una banda de piel desnuda de color azul brillante. Sus patas y pico son negras.

Esta especie habita una zona bastante limitada, se encuentra confinada al sector donde hay acacias en el sur de Etiopía cerca de Yavello (Javello), Mega, y Arero. Se desconoce porque no habita en zonas aledañas que parece poseen las características requeridas por esta especie.

Se alimenta principalmente de insectos, formando pequeñas bandadas. La reproducción por lo general comienza en marzo, cuando las aves construyen sus nidos en la zona superior de un árbol de acacia. Por lo general ponen de cinco a seis huevos color crema con pintas color lila. El nido posee forma globular con una entrada tubular en su parte superior. Es posible que además de los padres el nido sea visitado por jóvenes de nidadas previas que prestan ayuda para criar los pichones.

Referencias

Bibliografía

• dos Anjos, Luiz (2007). «Family Corvidae (Crows)». En Josep del Hoyo Josep del Hoyo; Andrew Elliott; David Christie, eds. Handbook of the Birds of the World. 9. Bush-shrikes to Old World Sparrows. Barcelona: Lynx Editions. ISBN 978-84-96553-50-7.
• Fry, C. Hilary; Stuart Keith and Emil K. Urban (2000). The Birds of Africa Volume VI. London: Academic Press. ISBN 0-12-137306-1.
• Madge, Steve; Hilary Burn (1994). Crows and Jays: A Guide to the Crows, Jays, and Magpies of the World. Boston: Houghton Mifflin Company. ISBN 0-395-67171-X.
• Gedeon, Kai (2006) Observations on the biology of the Ethiopean Bush Crow Zavattariornis stresemanni Bulletin of the African Bird Club Vol 13 No 2 pages 178 - 188

Zavattariornis stresemanni Zavattariornis generoko animalia da. Hegaztien barruko Corvidae familian sailkatua dago.

Erreferentziak

• World Bird Names

Ikus, gainera

• Zavattariornis
• Corvidae

Etiopiannaakka (Zavattariornis stresemanni)^[2] on varisten heimoon kuuluva varpuslintu. Se on sukunsa ainoa laji.

Tuntomerkit

Etiopiannaakka on 30 cm pitkä. Sillä on vaaleanharmaa pää ja vartalo sekä mustat siivet ja pyrstö. Silmän ympärillä on paljas, sininen alue. Sukupuolet ovat samannäköiset, mutta nuoret yksilöt ovat hieman likaisemman harmaita.^[3]

Levinneisyys

Etiopiannaakkaa esiintyy kotoperäisenä Etelä-Etiopiassa. Sen tärkeintä elinaluetta ovat Yabellon luonnonsuojelualueen eteläosat. Laji levinneisyysalueet ovat laikuttaisia ja pieniä. Lajin kannaksi arvioidaan 10 000–20 000 yksilöä ja se on luokiteltu erittäin uhanalaiseksi.^[1]

Elinympäristö

Etiopiannaakka elää savanneilla, joilla kasvaa jonkin verran akasiapensaita. Se voi elää myös ihmisasutuksen läheisyydessä.^[1]

Lisääntyminen

Etiopiannaakka pesii helmi–maaliskuussa. Laji pesii ryhmissä, joissa pesimättömät parit auttavat pesiviä pareja. Pesä rakennetaan akasiapensaan latvaan 2,5–10 metrin korkeuteen. Munia on enimmillään kuusi. Lajin on havaittu pesivän myös touko–kesäkuussa, joten se saattaa pesiä kahdesti vuodessa tai pesimäkausi voi olla pidempi.^[1]

Ravinto

Etiopiannaakka käyttää ravinnokseen pääasiassa niveljalkaisia.^[1]

Lähteet

Zavattariornis stresemanni

Le Corbin de Stresemann (Zavattariornis stresemanni) est une espèce de passereau de la famille des corvidés.

Le Corbin de Streseman a été découvert en 1937. Edoardo Zavattari (1883-1972), ancien directeur de l'institut zoologique de l'université de Rome, l'a observé en avril 1937 au cours de deux expéditions dans le bush en Éthiopie du Sud. L'oiseau a reçu son nom en l'honneur de l'ornithologue allemand Erwin Stresemann (1889-1972). C'est en 1938 qu'il a été décrit pour la première fois par l'ornithologue italien Edgardo Moltoni (1896-1980) et a été classifié dans le genre monotype Zavattariornis.

Aspect et mode de vie

Ces oiseaux, semblables aux étourneaux, atteignent une taille de 30 cm. Ils sont gris bleu dans leur apparence générale mais avec une coloration presque blanche sur le front. La gorge et la poitrine sont couleur crème et les plumes de parade ainsi que la queue d'un noir brillant. Les pointes des plumes ont tendance à devenir brune. Le mâle et la femelle se ressemblent, les jeunes sont colorés d'une façon qui leur donne une apparence un peu plus sale. L'iris est brun et les yeux sont entourés d'un cercle bleu clair dû à la peau nue de leur visage. Bec, pieds et pattes sont noirs.

En dehors de la période de reproduction, ces oiseaux sont très sociables. Ils aiment la compagnie des Spréos à calotte blanche (Spreo albicapillus) et forment des groupes de quatre à dix individus. Ils se nourrissent d'insectes.

Aire de répartition

Sa présence se limite aux savanes épineuses, aux savanes à herbe courte et aux savanes d'acacias dans le sud de l'Éthiopie à proximité des localités de Yavello, Mega et Arero.

Reproduction

Les nids sont construits à une hauteur de 6 m dans des buissons d'acacias. La ponte se compose habituellement de cinq à six œufs de couleur crème avec les taches couleur lilas. Le nid est convexe avec une entrée tubulaire sur le dessus. L'incubation a lieu de février-mars jusqu'à mai-juin. En raison de la longueur de cette période, il est possible que plusieurs couples visitent le nid et que des jeunes des couvées précédentes aident à élever les petits derniers.

Références externes

• (en) Référence Congrès ornithologique international : (consulté le 18 mai 2015)
• (en) Référence Zoonomen Nomenclature Resource (Alan P. Peterson) : Zavattariornis stresemanni dans Passeriformes
• (fr+en) Référence Avibase : Zavattariornis stresemanni Moltoni, 1938 (+ répartition) (consulté le 26 avril 2016)
• (fr+en) Référence ITIS : Zavattariornis stresemanni Moltoni, 1938
• (en) Référence Animal Diversity Web : Zavattariornis stresemanni
• (en) Référence NCBI : Zavattariornis stresemanni (taxons inclus)
• (en) Référence UICN : espèce Zavattariornis stresemanni Moltoni, 1938 (consulté le 18 mai 2015)
• (en) Référence Fonds documentaire ARKive : Zavattariornis stresemanni
• (de) Cet article est partiellement ou en totalité issu de l’article de Wikipédia en allemand intitulé .

Il corvide di Zavattari o corvo di boscaglia abissino (Zavattariornis stresemanni Moltoni, 1938) è un uccello passeriforme della famiglia dei Corvidi, nell'ambito della quale rappresenta l'unica specie ascritta al genere Zavattariornis Moltoni, 1938^[2].

Etimologia

Il nome scientifico del genere, Zavattariornis, rappresenta un omaggio a Edoardo Zavattari (che ne reperì gli esemplari in seguito utilizzati per la descrizione scientifica), cui si somma la parola greca ορνις (ornis, "uccello"): il nome della specie, stresemanni, rappresenta invece un omaggio a Erwin Stresemann.

Descrizione

Dimensioni

Misura 28 cm di lunghezza, per 130 g di peso^[3].

Aspetto

Esemplare impagliato a Nairobi.

Si tratta di uccelli dall'aspetto massiccio ma slanciato, muniti di testa arrotondata e allungata con becco conico sottile e appuntito, ali appuntite e non molto lunghe, coda lunga circa la metà del corpo e dall'estremità squadrata e forti zampe.

Il piumaggio è dominato dal grigio cenere molto chiaro, che sfuma nel bianco-panna su faccia (fronte, guance, sopracciglio e gola), ventre e sottocoda, mentre le remiganti e la coda sono di colore nero.

Il becco è nero, e anche le zampe sono nerastre: gli occhi sono di colore bruno scuro, con una mascherina glabra di colore blu cobalto che dai lati del becco giunge all'occhio, circondandolo. Il cerchio perioculare può essere ingrandito dall'animale, riducendo l'occhio a una fessura e scoprendo l'area glabra nella zona temporale, di colore rosa e normalmente coperta dalle piume circostanti: tale proprietà viene sfruttata dai corvidi di Zavattari durante il corteggiamento, ma molto verosimilmente anche a fini di termoregolazione^[4].

Biologia

Il corvide di Zavattari è un uccello diurno, che vive in piccoli gruppi di 6-7 esemplari, i quali passano la notte insieme su un albero, ma all'alba si separano, coi singoli uccelli o le coppie (sebbene talvolta i gruppi rimangano coesi anche durante il giorno, ad esempio quando il cibo è abbondante) che si muovono alla ricerca di cibo al suolo o fra i cespugli, non di rado assieme ad altre specie dalle abitudini simili, come storni corona bianca, buceri beccogiallo, tessitori dei bufali beccorosso e storni superbi^[5].

Si tratta di uccelli molto vocali, che si tengono in contatto quasi costante fra loro mediante richiami metallici mentre sono al suolo e gracchi nasali mentre sono in volo, mentre gli animali intenti a socializzare (durante la costruzione del nido, l'alimentazione o la tolettatura) emettono bassi richuami gracchianti^[3].

Alimentazione

La dieta del corvide di Zavattari è quasi esclusivamente insettivora: questi uccelli si nutrono infatti in massima parte di piccoli invertebrati e più specificatamente di insetti (coleotteri, cavallette e falene) e delle loro larve (che da sole costituiscono circa i tre quarti della dieta di questo uccello)^[6].

Questi uccelli reperiscono il cibo in maniera simile ai tordi, infilando il becco nella porzione superficiale del suolo ed aprendolo, per poi catturare gli animali che emergono in superficie: essi sono stati inoltre osservati ispezionare i rami e il fogliame di alberi e cespugli (dando prova di essere in grado di camminare piuttosto agilmente sui rami verticali, in maniera simile ai rampichini) alla ricerca degli insetti che in esso si annidano, così come catturare prede in volo^[6]. Il becco sottile e allungato viene utilizzato come una sonda: esso viene infilato nei mucchi di letame per estrarne gli insetti coprofagi e le loro larve, per penetrare il legno marcio e la corteccia dei tronchi caduti alla ricerca degli insetti annidati sotto di esso e addirittura per cercare ed estrarre i parassiti nella pelle della groppa del bestiame, in maniera simile alle bufaghe^[5].
Quando il corvide di Zavattari reperisce una preda, vola immediatamente sul ramo di un albero nelle vicinanze, dove la finisce col becco tenendola con una zampa prima di nutrirsene.

Riproduzione

Si tratta di uccelli monogami, le cui coppie rimangono assieme per la vita: la riproduzione avviene immediatamente dopo le prime piogge (febbraio-marzo), che scatenano la fregola^[3].
Il corteggiamento ha inizio quando uno dei partner posiziona simbolicamente una fibra vegetale nel luogo dove verrà costruito il nido, fissandola al ramo con terriccio masticato per essere reso appiccicoso: i due esemplari della coppia cominciano a mostrare eccitazione, espandendo l'area glabra perioculare e staccando alcune foglie, che vengono lasciate cadere al suolo. In seguito, i due partner cominciano a inseguirsi ritualmente, prima di accoppiarsi e dare inizio alla costruzione vera e propria del nido^[5].

Il nido è piuttosto voluminoso (60 cm di diamentro) ed ha un'inusuale forma globosa, essendo formato da un'alta coppa che superiormente si avvolge su sé stessa formando una camera di cova interna che ha diametro pari all'incirca alle dimensioni dell'occupante: esso viene costruito in cima a un albero di acacia a 5-6 metri dal suolo, utilizzando rametti spinosi per la parte esterna e fili d'erba secca e sterco vaccino essiccato per la camera di cova. I corvidi di Zavattari nidificano generalmente da soli, ma capita di osservare piccole colonie di 4-5 nidi concentrati in un singolo luogo, ciascuno su un proprio albero: i nidi vengono generalmente riparati e riutilizzati anno dopo anno, ma la cerimonia di costruzione del nido che precede l'accoppiamento viene ripetuta tutti gli anni^[5].

All'interno del nido, la femmina depone fino a sei uova di color crema, munite di rada maculatura violacea concentrata all'estremità ottusa: la cova dura circa due settimane ed è a carico della sola femmina (imbeccata e sorvegliata dal maschio). I pulli, ciechi ed implumi, vengono accuditi e imbeccati da ambedue i sessi, e in tal modo s'involano a tre settimane dalla schiusa e si rendono indipendenti (generalmente aggregandosi allo stormo di nascita, soprattutto per quanto riguarda i maschi) attorno ai due mesi di vita.
Similmente a quanto avviene in altri corvidi, anche nel corvide di Zavattari capita che le coppie riproduttive vengano aiutate durante l'allevamento della prole da esemplari terzi (solitamente uno, ma talvolta anche fino a quattro), che non di rado visitano più nidi durante questa loro attività cooperativa^[5].

Distribuzione e habitat

Il corvide di Zavattari è endemico dell'Etiopia, della quale occupa una piccola area compresa fra le città di Javello, Mega e Arero, nell'estremo sud dell'Oromia.

L'habitat di questi uccelli è rappresentato dalla savana erbosa con presenza di macchie alberate a predominanza di acacia e Commiphora, preferibilmente nelle vicinanze delle aree coltivate e dei pascoli^[3]: l'areale di questi uccelli è strettamente legato alle aree con isoterma inferiore ai 20 °C, il che di fatto ne limita la distribuzione alla fascia fra i 1300 e i 1800 m di quota^[7].

Tassonomia

La tassonomia del corvide di Zavattari è stata piuttosto tormentata: fin dalla sua classificazione scientifica questo uccello ha subito numerose riclassificazioni, in virtù di alcune caratteristiche aberranti (la conformazione del palato, la modalità di foraggiamento, le aree glabre colorate ed espandibili sulla faccia, la tendenza ad essere parassitato da mallofagi) che sembrerebbero avvicinarlo agli sturnidi piuttosto che ai corvidi. Ancora adesso non si è sicuri della sua effettiva appartenenza ai corvidi^[2], con alcuni autori che ne hanno addirittura proposta la classificazione in una propria famiglia monotipica, Zavattariornithidae: le analisi molecolari, tuttavia, hanno confermato l'appartenenza di questo uccello al clade centrale dei corvidi (contenente le specie più rappresentative della famiglia, come corvi propriamente detti, gazze e ghiandaie), del quale occuperebbe una posizione molto basale, rappresentando verosimilmente una specie relitta imparentata con l'ultimo antenato comune del clade^[8].

Note

Krūmu vārna jeb Etiopijas krūmu vārna (Zavattariornis stresemanni) ir vārnu dzimtas (Corvidae) putnu suga, kas ir vienīgā suga krūmu vārnu ģintī (Zavattariornis).^[1] Ģeogrāfisko variāciju nav.^[1]

Izplatības areāls krūmu vārnai ir ļoti neliels. Tā dzīvo akāciju krūmu audzēs Etiopijas dienvidos.^[2]

Izskats

Krūmu vārna ir nedaudz lielāka nekā zilais sīlis (Cyanocitta cristata). Ķermeņa garums ap 28 cm, svars 130 g.^[3] Apspalvojums gaiši zilganpelēks, bet galvas virsa un pavēdere balta. Spārni un aste melna ar metālisku spīdumu. Kājas un knābis melni, bet āda ap tumši brūnajām acīm koši zila. Abi dzimumi izskatās vienādi. Jaunie putni nav tik koši un kontrastaini.^[2]

Barība

Krūmu vārna parasti barojas nelielos baros, kas sastāv no 4—10 indivīdiem.^[2] Krūmu vārnas pamatbarība ir kukaiņi, to kāpuri un kūniņas, kurus tā izrok no lielo zālēdāju mēslu kaudzēm. Krūmu vārna ķer arī lidojošos kukaiņus, kā arī pārbauda lielo dzīvnieku muguras, meklējot ādas parazītus uz tiem.^[2]

Ligzdošana

Ligzdot krūmu vārna sāk martā. Tā vij ligzdu akācijas krūmā, ieslēptu aiz akācijas dzeloņiem. Tai ir lodes forma, ar ieeju no augšas. Dējumā parasti ir 5—6 olas. Tās ir krēmīgi baltas ar nelieliem violetiem raibumiņiem. Iespējams, ka ligzdojošam pārim jaunos putnēnus palīdz izbarot iepriekšējā gada bērni.

Atsauces

De acaciagaai (Zavattariornis stresemanni) is een zangvogel uit de familie Corvidae (kraaien). De vogel werd in 1938 door Edgardo Moltoni geldig beschreven en als eerbetoon vernoemd naar de Duitse dierkundige Erwin Stresemann. Het is een bedreigde, endemisch in zuidelijk Ethiopië.

Kenmerken

De vogel is 28 cm lang. De vogel is onmiskenbaar; een typische kraai-achtige vogel, overwegend lichtgrijs met een zwarte staart en vleugels. Ook de snavel en de poten zijn zwart en de iris is bruinzwart en rond het oog een donkerblauw gekleurde naakte huid.^[2]

Verspreiding en leefgebied

Deze komt voor in Zuid-Ethiopië. In de regio Oromia en de zone Borena in een beperkt aantal terreinen binnen een gebied dat 160 kilometer lang en 100 kilometer breed is, rond de plaatsen Yabello, Arero en Mega. Een nationaal park in Yabella is een belangrijk bolwerk voor de soort. Het leefgebied is op 1700 meter boven zeeniveau gelegen savanne met kort gras en verspreid staande bomen of struiken uit het geslacht Acacia De vogel wordt ook aangetroffen in de buurt van menselijke nederzettingen.^[1]

Status

De acaciagaai heeft een beperkt verspreidingsgebied en daardoor is de kans op uitsterven aanwezig. De grootte van de populatie werd in 2016 door BirdLife International geschat op tien tot twintig duizend individuen en de populatie-aantallen nemen af door habitatverlies. Het leefgebied wordt aangetast omdat het gebied geschikt wordt gemaakt voor meer intensieve beweiding zodat veetelers daar permanent kunnen wonen, in plaats van begrazing door wilde dieren of extensieve beweiding door nomaden. Om deze redenen staat deze soort als bedreigd op de Rode Lijst van de IUCN.^[1]

Boranakråke (Zavattariornis stresemanni) er monotypisk og eneste arter i slekten Zavattariornis, som tilhører underfamilien Corvinae i kråkefamilien (Corvidae).

Biologi

Arten trives på savanne og er endemisk for området rundt de to landsbyene Yabelo og Mega i Sør-Etiopia, tett på riksgrensen mot Kenya. Den er nært knyttet til trær i akasieslekten (Acacia) og tornebusker i slekten Commiphora.^[1]

Boranakråke blir omkring 28 cm lang og veier cirka 130 g. Den har blekgrå fjærdrakt med sorte vinger og sort stjert. Også de undre ekstremitetene og nebbet er sort, og sort kileformet hud løper videre fra nebbroten og «gjennom» de sorte øyene på fuglen.

Inndeling

Inndelingen under følger HBW Alive og er i henhold til dos Anjos & Bonan (2017)^[2]. Oppdelingen av underfamilier følger Jønsson et al. (2016).^[3] Alle norske navn følger Norsk navnekomité for fugl (NNKF) og er i henhold til Syvertsen et al. (2008),^[4] med unntak for navn gitt i parentes. Disse har fortsatt ikke fått avklart sitt norske navn og må derfor kun betraktes som beskrivende uttrykk.

• Passeriformes, spurvefugler
  • Passeri, sangfugler
    • Corvoidea
      • Corvidae, kråkefamilien
        • Corvinae
          • Garrulus
          • Zavattariornis
            • Z. stresemanni, boranakråke
          • Ptilostomus
          • Podoces, løpekråker
          • Pica
          • Nucifraga
          • Corvus

Referanser

Eksterne lenker

• (en) Boranakråke i Encyclopedia of Life
• (en) Boranakråke i Global Biodiversity Information Facility
• (en) Boranakråke hos NCBI
• (en) Boranakråke hos ITIS
• (en) Kategori:Zavattariornis stresemanni – bilder, video eller lyd på Wikimedia Commons
• Zavattariornis stresemanni – detaljert informasjon på Wikispecies

Vranka (lat. Zavattariornis) je rod vtákov z čeľade krkavcovité (Corvidae). Zahŕňa jediný druh vranka savanová (Zavattariornis stresemanni).

Iné projekty

• Commons ponúka multimediálne súbory na tému Vranka
• Wikidruhy ponúkajú informácie na tému Vranka

Stresemanns buskkråka^[2] (Zavattariornis stresemanni) är en fågel i familjen kråkfåglar inom ordningen tättingar.^[3]

Utbredning och systematik

Stresemanns buskkråka placeras som enda art i släktet Zavattariornis. Den förekommer enbart i södra Etiopien (Sidamo-provincen).^[3]

Status

IUCN kategoriserar arten som starkt hotad.^[1]

Namn

Fågelns svenska och vetenskapliga artnamn hedrar Erwin Friedrich Theodor Stresemann (1889-1972), tysk ornitolog, upptäcktsresande och samlare av specimen.^[4] Släktesnamnet hedrar Edoardo Zavattari (1883-1972), italiensk zoolog och upptäcktsresande.

Noter

1. ^ [a b] Birdlife International 2012 Zavattariornis stresemanni Från: IUCN 2015. IUCN Red List of Threatened Species. Version 2015.4 www.iucnredlist.org. Läst 2016-02-01.
2. ^ Sveriges ornitologiska förening (2017) Officiella listan över svenska namn på världens fågelarter, läst 2017-08-14
3. ^ [a b] Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood (2015) The eBird/Clements checklist of birds of the world: Version 2015 http://www.birds.cornell.edu/clementschecklist/download, läst 2016-02-11
4. ^ Jobling, J. A. (2016). Key to Scientific Names in Ornithology. Ur del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (red.) (2016). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. Hämtad från www.hbw.com.

Externa länkar

• Wikimedia Commons har media som rör Stresemanns buskkråka.
  Bilder & media
• Wikispecies har information om Zavattariornis stresemanni.
  Artförteckning

Zavattariornis stresemanni là một loài chim trong họ Corvidae.^[2]

Phạm vi phân bố của loài này là rất hạn chế, chỉ thu gọn trong vùng nhiều cây keo (Acacia) có gai ở miền nam Ethiopia gần Yabello (Jabello, Yavello), Mega và Arero. Loài này có bề ngoài và tập tính giống như chim sáo, cụ thể là với Creatophora cinerea (sáo yếm thịt) ở đông và nam châu Phi.

Chú thích

Tham khảo

• Dữ liệu liên quan tới Zavattariornis tại Wikispecies
• Phương tiện liên quan tới Zavattariornis tại Wikimedia Commons
• dos Anjos, Luiz (2007). “Family Corvidae (Crows)”. Trong del Hoyo, Josep; Elliott, Andrew; Christie, David. Handbook of the Birds of the World. 9. Bush-shrikes to Old World Sparrows. Barcelona: Lynx Editions. ISBN 978-84-96553-50-7.
• Fry, C. Hilary; Stuart Keith and Emil K. Urban (2000). The Birds of Africa Volume VI. London: Academic Press. ISBN 0-12-137306-1. Chú thích sử dụng tham số |coauthors= bị phản đối (trợ giúp)
• Madge, Steve; Hilary Burn (1994). Crows and Jays: A Guide to the Crows, Jays, and Magpies of the World. Boston: Houghton Mifflin Company. ISBN 0-395-67171-X. Chú thích sử dụng tham số |coauthors= bị phản đối (trợ giúp)
• Gedeon, Kai (2006). Observations on the biology of the Ethiopean Bush Crow Zavattariornis stresemanni. Bulletin of the African Bird Club Vol 13, No. 2, pages 178 - 188.
• Zavattariornis stresemanni tại Hệ thống Thông tin Phân loại Tích hợp (ITIS).
• Zavattariornis stresemanni tại Hệ thống Thông tin Phân loại Tích hợp (ITIS).
• Tham khảo Animal Diversity Web : Zavattariornis (tiếng Anh)
• Tham khảo Animal Diversity Web : Zavattariornis stresemanni (tiếng Anh)
• Zavattariornis tại trang Trung tâm Thông tin Công nghệ sinh học quốc gia Hoa Kỳ (NCBI).
• Zavattariornis stresemanni tại trang Trung tâm Thông tin Công nghệ sinh học quốc gia Hoa Kỳ (NCBI).
• Stresemann's Bushcrow from the Internet Bird Collection
• Anthony Disley line drawing of Stresemann's Bushcrow
• BirdLife Species Factsheet

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灰丛鸦（学名：Zavattariornis stresemanni），是鸦科灰丛鸦属的一种，为埃塞俄比亚的特有种。全球活动范围约为4,600平方千米。该物种的保护状况被评为濒危。

灰丛鸦的栖息地包括干燥的稀树草原和亚热带或热带的（低地）干燥疏灌丛。

参考文献

• Zavattariornis stresemanni. BirdLife.org. [2011-06-27].