View source for Bald ibis

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{{automatic Taxobox
| taxon = Geronticus
| fossil_range = [[Middle Miocene]] to Recent<br/>{{fossilrange|13|0}}
| name = ''Geronticus''
| image = Baldibisnest.JPG
| image_width = 240px
| image_caption = Nesting [[Southern Bald Ibis]] (''G. calvus'') with young.
| authority = [[Johann Georg Wagler|Wagler]], 1832
| subdivision_ranks = [[Species]]
| subdivision = 
''[[Geronticus calvus]]''<br />
''[[Geronticus eremita]]''<br />
For fossil species, see text
}}

The small [[bird]] [[genus]] '''''Geronticus''''' belongs to the [[ibis]] [[subfamily]] (Threskiornithinae). Its name is derived from the [[Greek (language)|Greek]] ''gérontos'' (γέρωντος, "old man")<ref>Brookes (2006) p.507</ref> in reference to the bald head of these dark-plumaged birds; in [[English (language)|English]] they are called '''bald ibises'''.

''Geronticus'' contains two living [[species]]. The [[Northern Bald Ibis]] (''G. eremita'') has a neck crest of elongated [[feather]]s. It is a [[Critically Endangered]] species found around the [[Mediterranean]]. Its range had expanded after the [[last glacial]] to [[Alps]] of [[Germany]] and even a bit further north, but it was rendered [[extinct]] there mainly due to [[habitat destruction]] and unsustainable [[hunting]]. The [[Southern Bald Ibis]] (''G. calvus'') with a red crown patch but no crest is classified as [[Vulnerable species|Vulnerable]] and found in [[subtropical]] southern [[Africa]].

[[File:Geronticus eremita.jpg|thumb|left|Wild [[Northern Bald Ibis]] (''G. eremita'') foraging in [[Morocco]]]]
Like most ibises, they gregarious long-legged wading birds with long down-curved [[Beak|bills]]; they form one subfamily of the [[Threskiornithidae]], the other subfamily being the [[spoonbill]]s. The two ''Geronticus'' species differ from other ibises in that they have unfeathered faces and heads, breed on cliffs rather than in trees, and prefer [[arid]] habitats to the [[wetlands]] used by their relatives. Their food contains fewer [[aquatic animals]] and more [[Terrestrial animal|terrestrial]] ones; they are known to gather together and feed on [[locust]] swarms, killing many of these notorious [[pest (organism)|pest]]s. This has also contributed to their decline however, as they were much affected by indiscriminate [[pesticide]] spraying in the mid-late 20th century, leading to their disappearance from many regions they used to inhabit.<ref>del Hoyo ''et al.'' (1992): p.472, Snow (1998): pp.146-147, Sinclair (2002) p.74</ref>

==Fossil record==
'''''Geronticus perplexus''''' is by far the oldest [[fossil]] assigned to the present genus. It is known only from a piece of [[distal]] right [[humerus]], found at [[Sansan]] ([[France]]) in [[Middle Miocene]] rocks of the [[Serravallian]] faunal stage [[MN 6 (faunal stage)|MN 6]] (about 12-14 mya). It was initially considered to be a [[heron]] and placed in the genera ''[[Ardea (genus)|Ardea]]'' and ''[[Proardea]]''. More [[plesiomorph]]ic than the living species, it seems to represent an ancient member of the ''Geronticus'' lineage, in line with the theory that most living ibis genera seem to have [[evolution|evolve]]d before 15 mya.<ref>Mlíkovský (2002)</ref>

'''''Geronticus apelex''''' is apparently the direct ancestor of the Southern Bald Ibis. Its remains were found in [[Early Pliocene]] deposits near [[Langebaanweg]] ([[South Africa]]) which date back about 5 million years.

What may be an ancestral [[Europe]]an form, '''''Geronticus balcanicus''''', was found in a [[Late Pliocene]] deposit near [[Slivnitsa]] ([[Bulgaria]]). It is hitherto only known from one left and one right [[carpometacarpus]] piece ([[NMNHS]] 14 and NMNHS 453, respectively) which are almost alike those of living bald ibises. Contemporaneous with these during the early [[MN18]] [[faunal stage]] &ndash; about 2 [[million years ago]] (mya) &ndash; birds entirely indistinguishable from the modern Northern Bald Ibis inhabited at least [[Spain]], if not the whole western Mediterranean region already. Thus, the extinct species may be the immediate ancestor of ''G. eremita'', which would have originated at the western extent of its range. Some authors even include the Bulgarian population in ''G. eremita'', but most are more cautious. ''G. balcanicus'' may also represent a lineage related but not ancestral to the Northern Bald Ibis, which inhabited the inland regions northeastwards of the European [[Alpide]]s and &ndash; like the immediate ancestor of ''G. eremita'' in this scenario &ndash; was isolated from the ancestors of ''G. calvus'' when [[gene flow]] across [[tropical]] Africa ceased.<ref>del Hoyo ''et al.'' (1992), Boev (1998, 2002), Mlíkovský (2002)</ref>

==Footnotes==
{{reflist}}

==References==
* Boev, Zlatozar (1998): Presence of Bald Ibises (''Geronticus'' Wagler, 1832) (Threskiornithidae - Aves) in the Late Pliocene of Bulgaria. ''Geologica Balcanica'' '''28''' (1–2): 45–52.
* Boev, Zlatozar (2002):Additional Material of ''Geronticus balcanicus'' Boev, 1998, and Precision of the Age of the Type Locality. ''Acta Zoologica Bulgarica'' '''52''' (2): 53–58 [English with Bulgarian abstract]. [http://e-ecodb.bas.bg/zb/sci/137_boev_2000_geronticus_additional_azb.pdf full text]
* Brookes, Ian (ed.) (2006): ''[[The Chambers Dictionary]]'' (9th ed.). Chambers, Edinburgh. ISBN  0550101853
* |del Hoyo, Josep; Elliott, Andrew & Sargatal, Jordi (eds.) (1992): ''[[Handbook of Birds of the World]]'' (Vol. 1: Ostrich to Ducks). Lynx Edicions, Barcelona. ISBN 84-87334-10-5
* Mlíkovský, Jirí (2002): ''Cenozoic Birds of the World'' (Part 1: Europe). Ninox Press, Prague. ISBN 80-901105-3-8 [http://www.nm.cz/download/JML-18-2002-CBE.pdf PDF fulltext]<!-- This should be treated with extreme caution as regards merging of species. Splits are usually good though. See also critical review in Auk121:623-627 here http://www.findarticles.com/p/articles/mi_qa3793/is_200404/ai_n9396879 -->
* Sinclair, Ian; Hockey, Phil & Tarboton, Warwick R. (2002): ''SASOL Birds of Southern Africa''. Struik, Cape Town ISBN 1-86872-721-1
* Snow, David W. & Perrins, Christopher M. (eds.) (1998): ''The Birds of the Western Palearctic'' (concise ed.). Oxford University Press. ISBN 019854099X

==External links==
{{Commons category}}
* [http://sn2000.taxonomy.nl/Taxonomicon/TaxonTree.aspx?id=51903 Genus ''Geronticus'']




{{Threskiornithidae}}

{{Ardeiformes-stub}}

{{Project Bird Genera}}
{{Wiki|{{PN}}}}
[[Category:Genera of Plataleiformes]]
[[Category:Threskiornithidae|*{{PN}}]]
[[Category:Threskiornithinae|*{{PN}}]]
[[Category:Geronticus|*]]