{{Short description|Genus of birds}} __NOTOC__ {{Automatic taxobox | fossil_range = Middle Miocene to recent<br/>{{fossilrange|13|0}} | image = Baldibisnest.JPG | image_caption = Nesting southern bald ibis (''G. calvus'') with young. | taxon = Geronticus | authority = Wagler, 1832 | type_species =''Tantalus calvus''<ref name=HM4>{{cite web |url= https://www.aviansystematics.org/4th-edition-checklist?viewfamilies=24 |title= Threskiornthidae |author=<!--Not stated--> |date= |website= aviansystematics.org |publisher= The Trust for Avian Systematics |access-date= 2023-07-27}}</ref> | type_species_authority = Boddaert, 1783 | 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 ''gérontos'' (γέρωντος, "old man")<ref>Brookes (2006) p.507</ref> in reference to the bald head of these dark-plumaged birds; in English, they are called '''bald ibises'''.

The genus was erected by the German naturalist Johann Georg Wagler in 1832.<ref>{{ cite journal | last=Wagler | first=Johann Georg | author-link=Johann Georg Wagler | year=1832 | title=Neue Sippen und Gattungen der Säugthiere und Vögel | journal=Isis von Oken | volume=1832 | at=cols 1218–1235 [1232] | language=German, Latin | url=https://biodiversitylibrary.org/page/26455535 }}</ref> The type species was subsequently designated as the southern bald ibis (''Geronticus calvus'').<ref>{{ cite book | last=Gray | first=George Robert | author-link=George Robert Gray | year=1840 | title=A List of the Genera of Birds: with an Indication of the Typical Species of Each Genus | place=London | publisher=R. and J.E. Taylor | page=67 | url=https://biodiversitylibrary.org/page/13668984 }}</ref><ref>{{ cite book | editor1-last=Mayr | editor1-first=Ernst | editor1-link=Ernst Mayr | editor2-last=Cottrell | editor2-first=G. William | year=1979 | title=Check-list of Birds of the World | volume=1 | edition=2nd | publisher=Museum of Comparative Zoology | place=Cambridge, Massachusetts | page=264 | url=https://biodiversitylibrary.org/page/16108826 }}</ref>

==Species== {{Species table |genus= Geronticus |authority-name=Wagler |authority-year=1832 |species-count=two|no-note=y|narrow-percent=75}}

{{Species table/row |name= northern bald ibis or waldrapp|binomial=Geronticus eremita |image=File:Waldrapp Geronticus eremita.jpg|image-size=180px |image-alt= |authority-name=Linnaeus |authority-year=1758 |authority-not-original=yes |range= Mediterranean |range-image= |range-image-size=180px |size=Has a neck crest of elongated feathers.<ref>{{cite iucn |author=BirdLife International |date=2018 |title=''Geronticus eremita'' |volume=2018 |article-number=e.T22697488A130895601 |doi=10.2305/IUCN.UK.2018-2.RLTS.T22697488A130895601.en |access-date=26 December 2023}}</ref> |habitat= Its range had expanded after the last glacial period to the Alps of Germany and even a bit further north,{{citation needed|date=December 2023}} but it was rendered extinct there mainly due to habitat destruction and unsustainable hunting. It is subject to ongoing reintroduction programs. |hunting= |iucn-status= EN |population= |direction= |subspecies= }}

{{Species table/row |name= southern bald ibis|binomial=Geronticus calvus |image=File:Southern Bald RWD7.jpg|image-size=180px |image-alt= |authority-name=Boddaert |authority-year=1783 |authority-not-original=yes |range= subtropical southern Africa |range-image= |range-image-size=180px |size=Has a red crown patch but no crest.<ref>{{cite iucn |author=BirdLife International |date=2016 |title=''Geronticus calvus'' |volume=2016 |article-number=e.T22697496A93617026 |doi=10.2305/IUCN.UK.2016-3.RLTS.T22697496A93617026.en |access-date=26 December 2023}}</ref> |habitat= |hunting= |iucn-status= VU |population= |direction= |subspecies= }} {{Species table/end}}

[[File:Geronticus eremita.jpg|thumb|left|Wild northern bald ibis (''G. eremita'') foraging in Morocco]] Like most ibises, they are gregarious long-legged wading birds with long down-curved bills; they form one subfamily of the Threskiornithidae, the other subfamily being the spoonbills. 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 ones; they are known to gather together and feed on locust swarms, killing many of these notorious pests. This has also contributed to their decline however, as they were much affected by indiscriminate pesticide spraying in the mid-to-late 20th century, leading to their disappearance from many regions.<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 (about 12-14 million years ago). It was initially considered to be a heron and placed in the genera ''Ardea'' and ''Proardea''. More plesiomorphic 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 evolved before 15 million years ago (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 five million years.

What may be an ancestral European 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 identical to those of living bald ibises. Contemporaneous with these during the early MN18 faunal stage &ndash; about two 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 Alpides 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]. [https://web.archive.org/web/20110815091243/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|0-550-10185-3}} * |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. {{Listed Invalid ISBN|80-901105-3-8}} [https://web.archive.org/web/20110520101755/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|0-19-854099-X}}

==External links== * [http://sn2000.taxonomy.nl Geronticus, Systema Naturae 2000] Navigate: Taxon Index, Genus Level, G * [http://focusingonwildlife.com/news/bald-ibis-by-adam-riley/ Bald Ibis by Adam Riley], Focusing on Wildlife

{{Threskiornithidae}} {{Pelecaniformes genera|A.|state=collapsed}} {{Taxonbar|from=Q913200}} {{Authority control}}

Category:Threskiornithidae Category:Bird genera Category:Serravallian first appearances Category:Extant Miocene first appearances