Rhea (bird): Difference between revisions

Rheas; Temporal range: Pleistocene-Holocene 0.126–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
	Two greater rheas
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Infraclass:	Palaeognathae
Order:	Rheiformes
Family:	Rheidae
Genus:	Rhea; Brisson, 1760
Type species
	Struthio americanus; Linnaeus, 1758
Species
	†R. anchorenense; †R. fossilis; †R. mesopotamica; †R. subpampeana; R. americana American rhea; R. pennata Darwin's rhea; R. tarapacensis Puna rhea (disputed);
Synonyms
	Rhea Moehring, 1752 pre-Linnaean; Touyou Lacépède, 1799; Tuyus Rafinesque, 1815; Pterocnemia G. R. Gray, 1870;

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Rheas (/ˈriːəz/ REE-əz), also known as ñandus^[a] (/njænˈduːz/ nyan-DOOZ) or South American ostrich,^[3]^[4] are moderately sized South American ratites (flightless birds without a keel on their sternum bone) of the order Rheiformes. They are distantly related to the African ostriches and Australia's emu (the largest and second-largest living ratites, respectively), with rheas placing just behind the emu in height and overall size.

Most taxonomic authorities recognize two extant species: the greater or American rhea (Rhea americana), and the lesser or Darwin's rhea (Rhea pennata). The International Union for Conservation of Nature (IUCN) classifies the puna rhea as another species instead of a subspecies of the lesser rhea. The IUCN currently rates the greater and puna rheas as near-threatened in their native ranges, while Darwin's rhea is of least concern, having recovered from past threats to its survival. In addition, the feral population of the greater rhea in Germany appears to be growing. However, control efforts are underway and seem to succeed in controlling the birds' population growth. Similarly to ostriches and emus, rheas are fairly popular livestock and pets, regularly kept and bred on farms, ranches, private parks, and by aviculturists, mainly in North and South America and Europe.

Etymology

The name "rhea" was used in 1752 by Paul Möhring and adopted as the English common name. Möhring named the rhea after the Greek Titan Rhea, whose Ancient Greek name (Ῥέα) is thought to come from ἔρα (éra, "ground"). This was fitting with the rhea being a flightless ground bird. Depending on the South American region, the rhea is known locally as ñandú guazu (Guaraní –or related Tupi nhandú-gûasú– meaning "big spider"^[5] most probably concerning their habit of opening and lowering alternate wings when they run),^{[citation needed]} ema (Portuguese), suri (Aymara and Quechua),^[6]^[7] or choique (Mapudungun). Nandu is the common name in many European languages and may sometimes be heard in English.^[3]

Taxonomy and systematics

The genus Rhea was introduced by French zoologist Mathurin Jacques Brisson in 1760 with the greater rhea (Rhea americana) as the type species.^[8]^[9]

Extant species

The genus contains two extant species and eight subspecies, although one subspecies is disputed:^[10]

Genus **Rhea** – Brisson, 1760 – two species
Common name	Scientific name and subspecies	Range	Size and ecology	IUCN status and estimated population
Greater rhea	Rhea americana (Linnaeus, 1758) Five subspecies R. a. americana (Linnaeus, 1758), live in the cerrados (bushlands) and caatinga of central and eastern Brazil. R. a. intermedia Rothschild & Chubb 1914, intermediate rhea of southeastern Brazil in Rio Grande do Sul and Uruguay R. a. nobilis Brodkorb 1939, eastern Paraguay, east of Rio Paraguay R. a. araneipes Brodkorb 1938, chaco of Paraguay to Bolivia and Mato Grosso in Brazil R. a. albescens Lynch & Holmberg 1878, plains of Argentina south of Rio Negro	Argentina, Bolivia, Brazil, Paraguay and Uruguay	Size: Habitat: Diet:	NT
Darwin's rhea or lesser rhea	Rhea pennata d'Orbigny, 1834 Two subspecies R. p. garleppi (Chubb 1913), puna/Garlepp's rhea of southeastern Peru, southwestern Bolivia and northwestern Argentina. It is included in R. tarapacensis by The International Union for Conservation of Nature (IUCN). R. p. pennata d'Orbigny 1834, Darwin's lesser rhea of Patagonian steppes in southern Argentina and southern Chile	Altiplano and Patagonia in South America	Size: Habitat: Diet:	LC

Rhea pennata was not always in the genus Rhea. In 2008, the SACC, the last holdout, approved merging the genera Rhea and Pterocnemia on August 7, 2008. This merging of genera leaves only the genus Rhea.^[11] A former fourth species of rhea, Rhea nana, was described by Lydekker in 1894 based on a single egg found in Patagonia,^[12] but today no major authorities consider it valid.

Fossils

†R. anchorenense (Ameghino & Rusconi 1932) [Rhea americana anchorenense Amcghino & Rusconi 1932]
†R. fossilis (Moreno & Mercerat 1891) [Pterocnemia fossilis (Moreno & Mercerat 1891); Rhea pampeana (Moreno & Mercerat 1891)]
†R. mesopotamica (Agnolín & Noriega 2012) [Pterocnemia mesopotamica Agnolín & Noriega 2012]
†R. subpampeana Moreno & Mercerat 1891

Description

Rheas are large, flightless birds with grey-brown plumage, long legs, and long necks, similar to an ostrich. Large males of R. americana can reach 170 cm (67 in) tall at the head, 100 cm (39 in) at the back^[13] and can weigh up to 40 kg (88 lb).^[14] The lesser rhea is smaller, with a height of 100 cm (39 in).^[13] Their wings are large for a flightless bird (250 cm (8.2 ft))^[13] and are spread while running, to act like sails.^[15] Unlike most birds, rheas have only three toes. Their tarsus has 18 to 22 horizontal plates on the front of it. They also store urine separately in an expansion of the cloaca.^[13]

Distribution and habitat

Rheas are from South America only and are limited within the continent to Argentina, Bolivia, Brazil, Chile, Paraguay, Peru and Uruguay. They are grassland birds, and both species prefer open land. The greater rheas live in open grasslands, pampas and chaco woodlands. They prefer to breed near water and prefer lowlands, seldom going above 1,500 metres (4,900 ft). On the other hand, the lesser rhea will inhabit most shrubland, grassland, even desert salt puna up to 4,500 metres (14,800 ft).^[13]^[16]^[17]

Feral populations in Europe

A small population of rheas has emerged in Mecklenburg-Western Pomerania, northeastern Germany, after several couples escaped from an exotic meat farm near Lübeck in the late 1990s. Contrary to expectations, the large birds adapted well to conditions in the German countryside.^[18] A monitoring system has been in place since 2008.^[19] By 2014, there was already a population of well over 100 birds in an area of 150 square kilometres (58 sq mi) between the river Wakenitz and the A20 motorway, slowly expanding eastward.^[20]

The population grew steadily for several years. By autumn 2018, their numbers had significantly increased to about 600. As such, local farmers claim increasing damage to their fields, and some biologists say the rheas pose a growing risk to local wildlife. Still protected by German natural conservation law, a local discussion developed regarding how to handle the situation. Eventually, Mecklenburg-Western Pomerania's government allowed limited hunting of the birds, explicitly to just reduce the population's growth and not to wipe them out. At this point, it was generally agreed that the rheas should be allowed to stay in the region. By spring 2021, just 247 rheas were counted; this development was attributed to both the hunting and the increased caution of the animals. Several had begun to avoid humans more than previously and retreated into the woods.^[21]^[22] Some members of this rhea population have also expanded into other areas; at least twice individual rheas who probably originated in Mecklenburg-Western Pomerania were sighted in Brandenburg's High Fläming Nature Park, over 200 kilometres (120 mi) from their usual range.^[23] By early 2023, 91 rheas were counted in Mecklenburg-Western Pomerania; the population decline was attributed to both hunting as well as harsher weather of previous years. By this point, German authorities believed a stable population of 50 adult birds would be optimal for the local ecosystem and agriculture. Researchers concluded that the feral population was subject to substantial fluctuations but remained healthy, adaptable, and entrenched in the area.^[24]

There also appears to be a small population of wild rheas in the United Kingdom. In March 2021, about 20 rheas were reportedly running free on a residential estate in Hertfordshire. Local police could not identify any owner, so they assumed they were wild birds. Once caught, authorities intend to place them in a suitable nature reserve to allow them to develop as a colony.^[25]

Behavior

Individual and flocking

Rheas tend to be silent birds, except when they are chicks or the male seeks a mate. During the breeding season, the male will attempt to attract females by calling. This call is a loud booming noise. While calling like this, they will lift the front of their body and ruffle their plumage, all while keeping their neck stiff. They will then extend and raise their wings and run short distances, alternating with their wings. He may then single out a female and walk alongside or in front of her with a lowered head and spread wings. If the female notices him, he will wave his neck back and forth in a figure eight. Finally, a female may offer herself, and copulation will commence.^[13]

During the non-breeding season they may form flocks of between 20 and 25 birds,^[26] although the lesser rhea forms smaller flocks than this. When in danger, they flee in a zigzag course, using one wing and the other, similar to a rudder. During the breeding season, the flocks break up.^[13]

Diet

Mostly, rheas are herbivorous and prefer broad-leafed plants, but they also eat fruits, seeds, roots, and insects such as grasshoppers, small reptiles, and rodents.^[13] Young rheas eat only insects for the first few days. Outside the breeding season, they gather in flocks and feed with deer and cattle.^[26]

Reproduction

Rheas are polygynandrous, with males courting between two and twelve females and females commonly mating with multiple dominant males during the breeding season. After mating, the male builds a nest where each female lays eggs. The nest is a simple scrape in the ground, lined with grass and leaves.^[15] The male incubates from ten to sixty eggs. The male will use a decoy system and place some eggs outside the nest, then sacrifice these to predators so they do not attempt to get inside the nest. The male may use another subordinate male to incubate his eggs while he finds another group of females to start a second nest with.^[13] The chicks hatch within 36 hours of each other. Right before hatching, the chicks begin to whistle.^[27] The group of females, meanwhile, may move on and mate with other males. While caring for the young, the males will charge at any perceived threat approaching the chicks, including female rheas and humans. The young reach full adult size in about six months but do not breed until they reach two years of age.^[15]

Status and conservation

The numbers of the greater and puna rhea are decreasing as their habitats shrink. Both are considered near threatened by the IUCN. The IUCN also states that they are both approaching vulnerable status.^[28]^[16]^[17]^[29] The lesser rhea is classified as least concern.^[30]

Human interaction

Rheas have many uses in South America. Feathers are used for feather dusters, skins are used for cloaks or leather, and their meat is a staple to many people.^[13]

Gauchos traditionally hunt rheas on horseback, throwing bolas or boleadoras—a throwing device consisting of three balls joined by rope—at their legs, which immobilises the bird.^[26] The rhea is pictured on Argentina's 1-centavo coin minted in 1987, and on the Uruguayan 5-peso coin.

Notes

^ alternatively spelt nandoo or nhandu

References

^ "Rhea sp". Avibase.
^ Moehring, Paul Heinrich Gerhard (1752). Avium Genera. p. 57. Retrieved 1 December 2024.
^ ^a ^b "nandu". The Chambers Dictionary (9th ed.). Chambers. 2003. ISBN 0-550-10105-5.
^ "rhea". Collins English Dictionary (13th ed.). HarperCollins. 2018. ISBN 978-0-008-28437-4.
^ Edelweiss, Frederico G. (1972). Gûaçú e usú na diacronia das línguas e dialetos Tupi-Guaranis (in Portuguese). Instituto de Estudoes Brasileiros.
^ Radio San Gabriel, "Instituto Radiofonico de Promoción Aymara" (IRPA) 1993, Republicado por Instituto de las Lenguas y Literaturas Andinas-Amazónicas (ILLLA-A) 2011, Transcripción del Vocabulario de la Lengua Aymara, P. Ludovico Bertonio 1612 (Spanish-Aymara-Aymara-Spanish dictionary)
^ Teofilo Laime Ajacopa (2007). Diccionario Bilingüe: Iskay simipi yuyayk’anch: Quechua – Castellano / Castellano – Quechua (PDF). La Paz, Bolivia: futatraw.ourproject.org.
^ Brisson, Mathurin Jacques (1760). Ornithologie, ou, Méthode Contenant la Division des Oiseaux en Ordres, Sections, Genres, Especes & leurs Variétés (in French and Latin). Paris: Jean-Baptiste Bauche. Vol. 1, p. 46, Vol. 5, p. 8.
^ Mayr, Ernst; Cottrell, G. William, eds. (1979). Check-list of Birds of the World. Vol. 1 (2nd ed.). Cambridge, Massachusetts: Museum of Comparative Zoology. p. 5.
^ Gill, Frank; Donsker, David, eds. (2019). "Ratites: Ostriches to Tinamous". World Bird List Version 9.1. International Ornithologists' Union. Retrieved 4 April 2019.
^ Remsen Jr., J. V.; et al. (7 August 2008). "Classification of birds of South America Part 01". South American Classification Committee. American Ornithologists' Union. p. Proposal#348. Retrieved 4 February 2009.
^ Knox, A.; Walters, M. (1994). Extinct and Endangered Birds in the Collections of the Natural History Museum. British Ornithologists' Club Occasional Publications. Vol. 1. British Ornithologists' Club.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Davies, S. J. J. F. (2003). "Rheas". In Hutchins, Michael (ed.). Grzimek's Animal Life Encyclopedia. Vol. 8 Birds I Tinamous and Ratites to Hoatzins (2nd ed.). Farmington Hills, MI: Gale Group. pp. 69–71. ISBN 0787657840.
^ Martin, W. C. L. (1835). An introduction to study of birds. London: Chiswick. p. 400.
^ ^a ^b ^c Davies, S. j. j. f. (1991). Forshaw, Joseph (ed.). Encyclopaedia of Animals: Birds. London: Merehurst Press. pp. 47–48. ISBN 1853911860.
^ ^a ^b BirdLife International (2012). "Greater Rhea Rhea americana". Data Zone. Retrieved 15 June 2012.
^ ^a ^b BirdLife International (2012). "Lesser Rhea Rhea pennata". Data Zone. Retrieved 15 June 2012.
^ Kulke, Ulli (2 January 2010). "Nandus – ein tierisches Einwanderungsproblem" [Rheas – an animal immigration problem]. Die Welt (in German). Retrieved 5 November 2014.
^ "Informationen der Arbeitsgruppe Nandumonitoring" [Information of the rhea monitoring working group] (in German). Retrieved 5 November 2014.
^ "Mecklenburg-Vorpommern: Nandus vergrößern ihren Lebensraum weiter" [Mecklenburg-Vorpommern: Rheas further extend their habitat]. Der Spiegel (in German). 5 November 2014. Retrieved 5 November 2014.
^ Burghardt, Peter (18 April 2021). "Nandus unter Beschuss" [Nandus under fire]. Süddeutsche Zeitung (in German). Retrieved 3 September 2021.
^ "Kontroverse Nandu-Jagd in MV" [Controversial nandu hunt in MV]. NDR (in German). 24 January 2021. Retrieved 3 September 2021.
^ "Fotografin lichtet schnellen Nandu im Hohen Fläming ab" [Photographer takes a photo of a fast nandu in High Fläming]. rbb24 (in German). 27 August 2021. Retrieved 3 September 2021.
^ "Wilde Nandus in Deutschland: Die Riesenvögel vom Schaalsee" [Wild rheas in Germany: The great birds of Schaalsee]. National Geographic (in German). 31 August 2023. Retrieved 24 May 2024.
^ BBC News (2021-03-26). "Rhea birds running wild on Hertfordshire housing estate". BBC News. Retrieved 2021-03-26.
^ ^a ^b ^c Coomber, Richard (1991). "Rheiformes: Rheas". In Gill Waugh (ed.). Birds of the World. Godalming, Surrey: Colour Library Books Ltd. pp. 8–9. ISBN 0862838061.
^ "Listen: Greater Rhea Nests Are Filled With Dozens of Whistling Eggs". Audubon. 2020-01-27. Retrieved 2022-01-26.
^ BirdLife International (2016). "Rhea tarapacensis". IUCN Red List of Threatened Species. 2016: e.T22728206A94974751. doi:10.2305/IUCN.UK.2016-3.RLTS.T22728206A94974751.en.
^ BirdLife International (2016). "Rhea americana". IUCN Red List of Threatened Species. 2016: e.T22678073A92754472. doi:10.2305/IUCN.UK.2016-3.RLTS.T22678073A92754472.en.
^ BirdLife International (2016). "Rhea pennata". IUCN Red List of Threatened Species. 2016: e.T22728199A94974489. doi:10.2305/IUCN.UK.2016-3.RLTS.T22728199A94974489.en.

External links

Rhea videos on the Internet Bird Collection
"Rhea" . Encyclopædia Britannica (11th ed.). 1911.

[3] ternatively spelt nandoo or nhandu

[1] "Rhea sp". Avibase.

[2] Moehring, Paul Heinrich Gerhard (1752). Avium Genera. p. 57. Retrieved 1 December 2024.

[:0-4] "nandu". The Chambers Dictionary (9th ed.). Chambers. 2003. ISBN 0-550-10105-5.

[5] "rhea". Collins English Dictionary (13th ed.). HarperCollins. 2018. ISBN 978-0-008-28437-4.

[6] Edelweiss, Frederico G. (1972). Gûaçú e usú na diacronia das línguas e dialetos Tupi-Guaranis (in Portuguese). Instituto de Estudoes Brasileiros.

[7] Radio San Gabriel, "Instituto Radiofonico de Promoción Aymara" (IRPA) 1993, Republicado por Instituto de las Lenguas y Literaturas Andinas-Amazónicas (ILLLA-A) 2011, Transcripción del Vocabulario de la Lengua Aymara, P. Ludovico Bertonio 1612 (Spanish-Aymara-Aymara-Spanish dictionary)

[8] Teofilo Laime Ajacopa (2007). Diccionario Bilingüe: Iskay simipi yuyayk’anch: Quechua – Castellano / Castellano – Quechua (PDF). La Paz, Bolivia: futatraw.ourproject.org.

[9] Brisson, Mathurin Jacques (1760). Ornithologie, ou, Méthode Contenant la Division des Oiseaux en Ordres, Sections, Genres, Especes & leurs Variétés (in French and Latin). Paris: Jean-Baptiste Bauche. Vol. 1, p. 46, Vol. 5, p. 8.

[10] Mayr, Ernst; Cottrell, G. William, eds. (1979). Check-list of Birds of the World. Vol. 1 (2nd ed.). Cambridge, Massachusetts: Museum of Comparative Zoology. p. 5.

[ioc-11] Gill, Frank; Donsker, David, eds. (2019). "Ratites: Ostriches to Tinamous". World Bird List Version 9.1. International Ornithologists' Union. Retrieved 4 April 2019.

[12] Remsen Jr., J. V.; et al. (7 August 2008). "Classification of birds of South America Part 01". South American Classification Committee. American Ornithologists' Union. p. Proposal#348. Retrieved 4 February 2009.

[13] Knox, A.; Walters, M. (1994). Extinct and Endangered Birds in the Collections of the Natural History Museum. British Ornithologists' Club Occasional Publications. Vol. 1. British Ornithologists' Club.

[Davies-14] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Davies, S. J. J. F. (2003). "Rheas". In Hutchins, Michael (ed.). Grzimek's Animal Life Encyclopedia. Vol. 8 Birds I Tinamous and Ratites to Hoatzins (2nd ed.). Farmington Hills, MI: Gale Group. pp. 69–71. ISBN 0787657840.

[15] Martin, W. C. L. (1835). An introduction to study of birds. London: Chiswick. p. 400.

[EoB-16] Davies, S. j. j. f. (1991). Forshaw, Joseph (ed.). Encyclopaedia of Animals: Birds. London: Merehurst Press. pp. 47–48. ISBN 1853911860.

[BLI-17] BirdLife International (2012). "Greater Rhea Rhea americana". Data Zone. Retrieved 15 June 2012.

[BLI1-18] BirdLife International (2012). "Lesser Rhea Rhea pennata". Data Zone. Retrieved 15 June 2012.

[19] Kulke, Ulli (2 January 2010). "Nandus – ein tierisches Einwanderungsproblem" [Rheas – an animal immigration problem]. Die Welt (in German). Retrieved 5 November 2014.

[20] "Informationen der Arbeitsgruppe Nandumonitoring" [Information of the rhea monitoring working group] (in German). Retrieved 5 November 2014.

[21] "Mecklenburg-Vorpommern: Nandus vergrößern ihren Lebensraum weiter" [Mecklenburg-Vorpommern: Rheas further extend their habitat]. Der Spiegel (in German). 5 November 2014. Retrieved 5 November 2014.

[22] Burghardt, Peter (18 April 2021). "Nandus unter Beschuss" [Nandus under fire]. Süddeutsche Zeitung (in German). Retrieved 3 September 2021.

[23] "Kontroverse Nandu-Jagd in MV" [Controversial nandu hunt in MV]. NDR (in German). 24 January 2021. Retrieved 3 September 2021.

[24] "Fotografin lichtet schnellen Nandu im Hohen Fläming ab" [Photographer takes a photo of a fast nandu in High Fläming]. rbb24 (in German). 27 August 2021. Retrieved 3 September 2021.

[25] "Wilde Nandus in Deutschland: Die Riesenvögel vom Schaalsee" [Wild rheas in Germany: The great birds of Schaalsee]. National Geographic (in German). 31 August 2023. Retrieved 24 May 2024.

[26] BBC News (2021-03-26). "Rhea birds running wild on Hertfordshire housing estate". BBC News. Retrieved 2021-03-26.

[Coomber-27] Coomber, Richard (1991). "Rheiformes: Rheas". In Gill Waugh (ed.). Birds of the World. Godalming, Surrey: Colour Library Books Ltd. pp. 8–9. ISBN 0862838061.

[28] "Listen: Greater Rhea Nests Are Filled With Dozens of Whistling Eggs". Audubon. 2020-01-27. Retrieved 2022-01-26.

[IUCN_tarapacensis-29] BirdLife International (2016). "Rhea tarapacensis". IUCN Red List of Threatened Species. 2016: e.T22728206A94974751. doi:10.2305/IUCN.UK.2016-3.RLTS.T22728206A94974751.en.

[IUCN_americana-30] BirdLife International (2016). "Rhea americana". IUCN Red List of Threatened Species. 2016: e.T22678073A92754472. doi:10.2305/IUCN.UK.2016-3.RLTS.T22678073A92754472.en.

[IUCN_pennata-31] BirdLife International (2016). "Rhea pennata". IUCN Red List of Threatened Species. 2016: e.T22728199A94974489. doi:10.2305/IUCN.UK.2016-3.RLTS.T22728199A94974489.en.

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@@ Line 21: / Line 21: @@
 * ''[[Darwin's rhea|R. tarapacensis]]'' <small>Puna rhea (disputed)</small>
 | synonyms =
+* ''Rhea'' <small>Moehring, 1752 [[Linnaean taxonomy|pre-Linnaean]]</small><ref>{{cite book |last1=Moehring |first1=Paul Heinrich Gerhard |title=Avium Genera |date=1752 |page=57 |url=https://www.biodiversitylibrary.org/item/104154#page/61/mode/1up |access-date=1 December 2024}}</ref>
-* ''Rhea'' <small>Moehring 1758 nomen dubium</small>
-* ''[[Pterocnemia]]'' <small>Gray 1870</small>
+* ''Touyou'' <small>[[Bernard Germain de Lacépède|Lacépède]], 1799</small>
-* ''Toujou'' <small>Lacépède 1801</small>
+* ''Tuyus'' <small>[[Constantine Samuel Rafinesque|Rafinesque]], 1815</small>
-* ''Tujus'' <small>Rafinesque 1815</small>
+* ''[[Pterocnemia]]'' <small>[[George Robert Gray|G. R. Gray]], 1870</small>
+|synonyms_ref=<ref>{{avibase|id=9E3B4EFBB03B3420|name=Rhea sp.}}</ref>
 }}
-The '''rheas''' ({{IPAc-en|'|r|iː|ə|z}} {{respell|REE|əz}}), also known as '''ñandus'''{{efn|alternatively spelt ''nandoo'' or ''nhandu''}} ({{IPAc-en|'|n|æ|n|d|uː|z}} {{respell|NAN|dooz}}) or '''South American ostriches''',<ref name=":0">{{Cite book|title=The Chambers Dictionary|publisher=Chambers|year=2003|isbn=0-550-10105-5|edition=9th|chapter=nandu}}</ref><ref>{{Cite book|title=Collins English Dictionary|publisher=HarperCollins|year=2018|isbn=978-0-008-28437-4|edition=13th|chapter=rhea}}</ref> are large [[ratite]]s ([[flightless bird]]s without a [[keel (bird anatomy)|keel]] on their [[sternum]] bone) in the order Rheiformes, native to [[South America]], distantly related to the [[Common ostrich|ostrich]] and [[emu]]. Most taxonomic authorities recognize two extant species: the [[Greater rhea|greater or American rhea]] (''Rhea americana''), and the [[Darwin's rhea|lesser or Darwin's rhea]] (''Rhea pennata''). The [[International Union for Conservation of Nature]] (IUCN) classifies the [[puna rhea]] as another species instead of a subspecies of the [[lesser rhea]]. The IUCN currently rates the greater and puna rheas as near-threatened in their native ranges, while Darwin's rhea is of least concern. In addition, a feral population of the greater rhea in Germany appears to be growing, though control efforts are underway, and seem to be succeeding in controlling the birds' population growth.
+'''Rheas''' ({{IPAc-en|'|r|iː|ə|z}} {{respell|REE|əz}}), also known as '''ñandus'''{{efn|alternatively spelt ''nandoo'' or ''nhandu''}} ({{IPAc-en|nj|æ|n|'|d|uː|z}} {{respell|nyan|DOOZ}}) or '''South American ostrich''',<ref name=":0">{{Cite book|title=The Chambers Dictionary|publisher=Chambers|year=2003|isbn=0-550-10105-5|edition=9th|chapter=nandu}}</ref><ref>{{Cite book|title=Collins English Dictionary|publisher=HarperCollins|year=2018|isbn=978-0-008-28437-4|edition=13th|chapter=rhea}}</ref> are moderately sized [[South America]]n [[ratite]]s ([[flightless bird]]s without a [[keel (bird anatomy)|keel]] on their [[sternum]] bone) of the order Rheiformes. They are distantly related to the African [[Ostrich|ostriches]] and Australia's [[emu]] (the largest and second-largest living ratites, respectively), with rheas placing just behind the emu in height and overall size.
+Most taxonomic authorities recognize two [[Extant taxon|extant]] species: the [[Greater rhea|greater or American rhea]] (''Rhea americana''), and the [[Darwin's rhea|lesser or Darwin's rhea]] (''Rhea pennata''). The [[International Union for Conservation of Nature]] (IUCN) classifies the [[puna rhea]] as another species instead of a subspecies of the [[lesser rhea]]. The IUCN currently rates the greater and puna rheas as near-threatened in their native ranges, while Darwin's rhea is of least concern, having recovered from past threats to its survival. In addition, the feral population of the greater rhea in Germany appears to be growing. However, control efforts are underway and seem to succeed in controlling the birds' population growth. Similarly to ostriches and emus, rheas are fairly popular livestock and pets, regularly kept and bred on farms, ranches, private parks, and by [[aviculture|aviculturists]], mainly in North and South America and Europe.
 ==Etymology==
-The name "rhea" was used in 1752 by [[Paul Möhring]] and adopted as the [[English language|English]] common name. Möhring named the rhea after the [[Titan (mythology)|Greek Titan]] [[Rhea (mythology)|Rhea]], whose [[Ancient Greek]] name ({{lang|grc|Ῥέα}}) is thought to come from {{lang|grc|ἔρα}} "ground". This was fitting with the rhea being a flightless ground bird. Depending on the South American region, the rhea is known locally as {{lang|gn|ñandú guazu}} ([[Guaraní language|Guaraní]], meaning big spider, most probably in relation to their habit of opening and lowering alternate wings when they run), {{lang|pt|ema}} ([[Portuguese language|Portuguese]]), {{lang|ay|suri}} ([[Aymara language|Aymara]] and [[Southern Quechua|Quechua]]),<ref>{{Ref Bertonio}}</ref><ref>{{Ref Laime}}</ref> or {{lang|arn|choique}} ([[Mapudungun language|Mapudungun]]). {{lang|mis|Nandu}} is the common name in many European languages and may sometimes also be heard in English.<ref name=":0"/>
+The name "rhea" was used in 1752 by [[Paul Möhring]] and adopted as the [[English language|English]] common name. Möhring named the rhea after the [[Titan (mythology)|Greek Titan]] [[Rhea (mythology)|Rhea]], whose [[Ancient Greek]] name ({{lang|grc|Ῥέα}}) is thought to come from {{lang|grc|ἔρα}} (''éra'', "ground"). This was fitting with the rhea being a flightless ground bird. Depending on the South American region, the rhea is known locally as {{lang|gn|ñandú guazu}} ([[Guaraní language|Guaraní]] –or related Tupi ''nhandú-gûasú''– meaning "big spider"<ref>{{cite book |last1=Edelweiss |first1=Frederico G. |title=Gûaçú e usú na diacronia das línguas e dialetos Tupi-Guaranis |lang=pt|year=1972 |publisher=[[Institute of Brazilian Studies at the University of São Paulo|Instituto de Estudoes Brasileiros]] |url=http://www.etnolinguistica.org/artigo:edelweiss-1969-guasu}}</ref> most probably concerning their habit of opening and lowering alternate wings when they run),{{citation needed|date=July 2024}} {{lang|pt|ema}} ([[Portuguese language|Portuguese]]), {{lang|ay|suri}} ([[Aymara language|Aymara]] and [[Southern Quechua|Quechua]]),<ref>{{Ref Bertonio}}</ref><ref>{{Ref Laime}}</ref> or {{lang|arn|choique}} ([[Mapudungun language|Mapudungun]]). {{lang|mis|Nandu}} is the common name in many European languages and may sometimes be heard in English.<ref name=":0"/>
 ==Taxonomy and systematics==
-[[File:Rhea dustbathing at Marwell zoo.JPG|thumb|right|[[Greater rhea]]s (''Rhea americana'') dustbathing: The two individuals on the left are [[leucistic]].]]
+[[File:Rhea dustbathing at Marwell zoo.JPG|thumb|right|[[Greater rhea]]s (''Rhea americana'') dustbathing at [[Marwell Zoo]]: The two individuals on the left are [[leucistic]].]]
 The [[genus]] ''Rhea'' was introduced by French zoologist [[Mathurin Jacques Brisson]] in 1760 with the [[greater rhea]] (''Rhea americana'') as the [[type species]].<ref>{{ cite book | last=Brisson | first=Mathurin Jacques | authorlink=Mathurin Jacques Brisson | year=1760 | title=Ornithologie, ou, Méthode Contenant la Division des Oiseaux en Ordres, Sections, Genres, Especes & leurs Variétés | language=fr, la | at=[https://biodiversitylibrary.org/page/36010444 Vol. 1, p. 46], [https://biodiversitylibrary.org/page/36294278 Vol. 5, p. 8] | place=Paris | publisher=Jean-Baptiste Bauche }}</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=5 | url=https://biodiversitylibrary.org/page/16108626 }}</ref>
 ===Extant species===
 The genus contains two extant species and eight subspecies, although one subspecies is disputed:<ref name=ioc>{{cite web| editor1-last=Gill | editor1-first=Frank | editor1-link=Frank Gill (ornithologist) | editor2-last=Donsker | editor2-first=David | year=2019 | title=Ratites: Ostriches to Tinamous | work=World Bird List Version 9.1 | url=https://www.worldbirdnames.org/bow/ratites/ | publisher=International Ornithologists' Union | access-date=4 April 2019 }}</ref>
+{{Species table |genus=Rhea |authority-name=[[Mathurin Jacques Brisson|Brisson]]|authority-year= 1760 |species-count=two|no-note=y|narrow-percent=75}}
-{| class="wikitable"
-|-
+{{Species table/row
-! Image !! Scientific name !! Common name !! Subspecies !! Distribution
+|name=Greater rhea|binomial=[[Rhea americana]]
-|-
-|[[File:Nandu Rhea americana Tierpark Hellabrunn-1.jpg|120px]] || ''[[Rhea americana]]'' <small>([[Linnaeus]], [[10th edition of Systema Naturae|1758]])</small> || [[Greater rhea]] ||
+|image=File:Nandu Rhea americana Tierpark Hellabrunn-1.jpg|image-size=180px |image-alt=
-* ''R. a. americana'' <small>([[Linnaeus]], [[10th edition of Systema Naturae|1758]])</small>, live in the [[cerrado]]s (bushlands) and [[caatinga]] of central and eastern [[Brazil]].
+|authority-name=[[Linnaeus]]|authority-year= [[10th edition of Systema Naturae|1758]]|authority-not-original=yes
-* ''R. a. intermedia'' <small>Rothschild & Chubb 1914</small>, intermediate rhea of southeastern [[Brazil]] in [[Rio Grande do Sul]] and [[Uruguay]]
+|range= [[Argentina]], [[Bolivia]], [[Brazil]], [[Paraguay]] and [[Uruguay]]
+|range-image=File:Rhea americana.svg
-* ''R. a. nobilis'' <small>Brodkorb 1939</small>, eastern [[Paraguay]], east of [[Rio Paraguay]]
+|range-image-size=180px
-* ''R. a. araneipes'' <small>Brodkorb 1938</small>, chaco of Paraguay to [[Bolivia]] and [[Mato Grosso]] in Brazil
+|size=
-* ''R. a. albescens'' <small>Lynch & Holmberg 1878</small>, plains of [[Argentina]] south of [[Rio Negro Province|Rio Negro]]
+|habitat=
-|| [[Argentina]], [[Bolivia]], [[Brazil]], [[Paraguay]] and [[Uruguay]]
+|hunting=
-|-
+|iucn-status= NT
-|[[File:Rhea pennata pennata (6).JPG|120px]] ||''[[Rhea pennata]]'' <small>d'Orbigny 1834</small> || [[Darwin's rhea]] or [[lesser rhea]] ||
+|population=
-* ''R. p. garleppi'' <small>(Chubb 1913)</small>, [[Puna grassland|puna]]/Garlepp's rhea of southeastern [[Peru]], southwestern Bolivia and northwestern Argentina. It is included in ''[[Puna Rhea|R. tarapacensis]]'' by The International Union for Conservation of Nature (IUCN).
+|direction=
-* ''R. p. pennata'' <small>d'Orbigny 1834</small>, Darwin's lesser rhea of [[Patagonia]]n [[steppes]] in southern Argentina and southern Chile
+|subspecies={{Collapsible list |expand=yes |title=Five subspecies |bullets=on
-|| Altiplano and Patagonia in South America
+| ''R. a. americana'' <small>([[Linnaeus]], [[10th edition of Systema Naturae|1758]])</small>, live in the [[cerrado]]s (bushlands) and [[caatinga]] of central and eastern [[Brazil]].
-|-
+| ''R. a. intermedia'' <small>Rothschild & Chubb 1914</small>, intermediate rhea of southeastern [[Brazil]] in [[Rio Grande do Sul]] and [[Uruguay]]
-|[[File:Rhea tarapacensis.jpg|120px]] || ''[[Rhea tarapacensis]]'' <small>Chubb 1913</small> || [[Puna rhea]] || No subspecies, but some consider it as a subspecies of the [[lesser rhea]]. The IUCN lists it as a third species.<ref name="IUCN_tarapacensis">{{cite iucn | author = BirdLife International | authorlink = BirdLife International | title = ''Rhea tarapacensis'' | volume = 2016 | page = e.T22728206A94974751 | year = 2016 | doi = 10.2305/IUCN.UK.2016-3.RLTS.T22728206A94974751.en }}</ref> || Tarapacá Rhea of northern [[Chile]] from [[Atacama]] to [[Tarapacá Region|Tarapacá]]
+| ''R. a. nobilis'' <small>Brodkorb 1939</small>, eastern [[Paraguay]], east of [[Rio Paraguay]]
-|}
+| ''R. a. araneipes'' <small>Brodkorb 1938</small>, chaco of Paraguay to [[Bolivia]] and [[Mato Grosso]] in Brazil
+|''R. a. albescens'' <small>Lynch & Holmberg 1878</small>, plains of [[Argentina]] south of [[Rio Negro Province|Rio Negro]]
+}}
+}}
+{{Species table/row
+|name=[[Darwin's rhea]] or [[lesser rhea]]|binomial=[[Rhea pennata]]
+|image=File:Rhea pennata pennata (6).JPG|image-size=180px |image-alt=
+|authority-name=d'Orbigny |authority-year= 1834|authority-not-original=
+|range= Altiplano and Patagonia in South America
+|range-image=File:Distribution of Rhea pennata.svg
+|range-image-size=180px
+|size=
+|habitat=
+|hunting=
+|iucn-status= LC
+|population=
+|direction=
+|subspecies={{Collapsible list |expand=yes |title=Two subspecies |bullets=on
+| ''R. p. garleppi'' <small>(Chubb 1913)</small>, [[Puna grassland|puna]]/Garlepp's rhea of southeastern [[Peru]], southwestern Bolivia and northwestern Argentina. It is included in ''[[Puna Rhea|R. tarapacensis]]'' by The International Union for Conservation of Nature (IUCN).
+| ''R. p. pennata'' <small>d'Orbigny 1834</small>, Darwin's lesser rhea of [[Patagonia]]n [[steppes]] in southern Argentina and southern Chile
+}}
+}}
+{{Species table/end}}
-''Rhea pennata'' was not always in the genus ''Rhea''. In 2008, the [[American Ornithological Society|SACC]], the last holdout, approved the merging of the genera, ''Rhea'' and ''Pterocnemia'' on August 7, 2008. This merging of genera leaves only the genus ''Rhea''.<ref>{{cite web| url=http://www.museum.lsu.edu/~Remsen/SACCProproster.html | title=Classification of birds of South America Part 01 | access-date=4 February 2009 | last=Remsen Jr. | first=J. V. |date = 7 August 2008 |page= Proposal#348| work=South American Classification Committee | publisher=American Ornithologists' Union |display-authors=etal}}</ref> A former fourth species of rhea, ''Rhea nana'', was described by [[Lydekker]] in 1894 based on a single [[egg (biology)|egg]] found in [[Patagonia]],<ref>{{Cite book|last1=Knox |first1=A. |last2=Walters |first2=M. |title=Extinct and Endangered Birds in the Collections of the Natural History Museum |series= British Ornithologists' Club Occasional Publications |volume=1 |year=1994 |publisher= British Ornithologists' Club }}</ref> but today no major authorities consider it valid.
+''Rhea pennata'' was not always in the genus ''Rhea''. In 2008, the [[American Ornithological Society|SACC]], the last holdout, approved merging the genera ''Rhea'' and ''Pterocnemia'' on August 7, 2008. This merging of genera leaves only the genus ''Rhea''.<ref>{{cite web| url=http://www.museum.lsu.edu/~Remsen/SACCProproster.html | title=Classification of birds of South America Part 01 | access-date=4 February 2009 | last=Remsen Jr. | first=J. V. |date = 7 August 2008 |page= Proposal#348| work=South American Classification Committee | publisher=American Ornithologists' Union |display-authors=etal}}</ref> A former fourth species of rhea, ''Rhea nana'', was described by [[Lydekker]] in 1894 based on a single [[egg (biology)|egg]] found in [[Patagonia]],<ref>{{Cite book|last1=Knox |first1=A. |last2=Walters |first2=M. |title=Extinct and Endangered Birds in the Collections of the Natural History Museum |series= British Ornithologists' Club Occasional Publications |volume=1 |year=1994 |publisher= British Ornithologists' Club }}</ref> but today no major authorities consider it valid.
 ===Fossils===
@@ Line 68: / Line 97: @@
 ==Description==
 [[File:Greater rhea close up.jpg|thumb|left|Greater rhea head close up]]
-Rheas are large, [[flightless bird]]s with grey-brown [[plumage]], long legs and long necks, similar to an [[ostrich]]. Large males of ''R. americana'' can reach {{cvt|170|cm}} tall at the head, {{cvt|100|cm}} at the back<ref name="Davies">{{Cite encyclopedia |last=Davies |first=S. J. J. F.|editor=Hutchins, Michael |encyclopedia=Grzimek's Animal Life Encyclopedia |title=Rheas |edition=2nd |year=2003 |publisher=Gale Group |volume=8 Birds I Tinamous and Ratites to Hoatzins |location=Farmington Hills, MI|isbn=0787657840 |pages=69–71}}</ref> and can weigh up to {{cvt|40|kg}}.<ref>{{Cite book|last1=Martin|first1=W. C. L. |title=An introduction to study of birds |url=https://archive.org/details/anintroductiont00martgoog |year=1835 |publisher=Chiswick |location=London |page=[https://archive.org/details/anintroductiont00martgoog/page/n414 400]}}</ref> The lesser rhea is smaller, with a height of {{cvt|100|cm}}.<ref name="Davies"/> Their wings are large for a flightless bird ({{cvt|250|cm|ft}})<ref name="Davies"/> and are spread while [[cursorial|running]], to act like [[sail]]s.<ref name=EoB>{{Cite book|editor=Forshaw, Joseph|first= S. j. j. f.|last= Davies|year=1991|title=Encyclopaedia of Animals: Birds|publisher= Merehurst Press|location=London|pages= 47–48|isbn= 1853911860}}</ref> Unlike most birds, rheas have only three toes. Their [[Tarsus (skeleton)|tarsus]] has 18 to 22 horizontal plates on the front of it. They also store [[urine]] separately in an expansion of the [[cloaca]].<ref name="Davies"/>{{clear left}}
+Rheas are large, [[flightless bird]]s with grey-brown [[plumage]], long legs, and long necks, similar to an [[ostrich]]. Large males of ''R. americana'' can reach {{cvt|170|cm}} tall at the head, {{cvt|100|cm}} at the back<ref name="Davies">{{Cite encyclopedia |last=Davies |first=S. J. J. F.|editor=Hutchins, Michael |encyclopedia=Grzimek's Animal Life Encyclopedia |title=Rheas |edition=2nd |year=2003 |publisher=Gale Group |volume=8 Birds I Tinamous and Ratites to Hoatzins |location=Farmington Hills, MI|isbn=0787657840 |pages=69–71}}</ref> and can weigh up to {{cvt|40|kg}}.<ref>{{Cite book|last1=Martin|first1=W. C. L. |title=An introduction to study of birds |url=https://archive.org/details/anintroductiont00martgoog |year=1835 |publisher=Chiswick |location=London |page=[https://archive.org/details/anintroductiont00martgoog/page/n414 400]}}</ref> The lesser rhea is smaller, with a height of {{cvt|100|cm}}.<ref name="Davies"/> Their wings are large for a flightless bird ({{cvt|250|cm|ft}})<ref name="Davies"/> and are spread while [[cursorial|running]], to act like [[sail]]s.<ref name=EoB>{{Cite book|editor=Forshaw, Joseph|first= S. j. j. f.|last= Davies|year=1991|title=Encyclopaedia of Animals: Birds|publisher= Merehurst Press|location=London|pages= 47–48|isbn= 1853911860}}</ref> Unlike most birds, rheas have only three toes. Their [[Tarsus (skeleton)|tarsus]] has 18 to 22 horizontal plates on the front of it. They also store [[urine]] separately in an expansion of the [[cloaca]].<ref name="Davies"/>{{clear left}}
 ==Distribution and habitat==
 [[File:Nandu, Parque Luro, La Pampa, Argentina.jpg|thumb|A rhea at the Parque Luro, Argentina]]
-Rheas are from [[South America]] only and are limited within the continent to [[Argentina]], [[Bolivia]], [[Brazil]], [[Chile]], [[Paraguay]], [[Peru]] and [[Uruguay]]. They are grassland birds and both species prefer open land. The greater rheas live in open grasslands, [[pampa]]s and [[wiktionary:chaco|chaco]] woodlands. They prefer to breed near water and prefer lowlands, seldom going above {{convert|1500|m}}. On the other hand, the lesser rhea will inhabit most [[shrubland]], grassland, even desert salt [[puna grassland|puna]] up to {{convert|4500|m}}.<ref name="Davies"/><ref name=BLI>{{cite web| url=http://www.birdlife.org/datazone/speciesfactsheet.php?id=2| title=Greater Rhea Rhea americana | access-date=15 June 2012 | author=BirdLife International | year=2012| work=Data Zone}}</ref><ref name=BLI1>{{cite web| url=http://www.birdlife.org/datazone/speciesfactsheet.php?id=3 | title=Lesser Rhea Rhea pennata | access-date=15 June 2012 | author=BirdLife International | year=2012| work=Data Zone}}</ref>
+Rheas are from [[South America]] only and are limited within the continent to [[Argentina]], [[Bolivia]], [[Brazil]], [[Chile]], [[Paraguay]], [[Peru]] and [[Uruguay]]. They are grassland birds, and both species prefer open land. The greater rheas live in open grasslands, [[pampa]]s and [[wiktionary:chaco|chaco]] woodlands. They prefer to breed near water and prefer lowlands, seldom going above {{convert|1500|m}}. On the other hand, the lesser rhea will inhabit most [[shrubland]], grassland, even desert salt [[puna grassland|puna]] up to {{convert|4500|m}}.<ref name="Davies"/><ref name=BLI>{{cite web| url=http://www.birdlife.org/datazone/speciesfactsheet.php?id=2| title=Greater Rhea Rhea americana | access-date=15 June 2012 | author=BirdLife International | year=2012| work=Data Zone}}</ref><ref name=BLI1>{{cite web| url=http://www.birdlife.org/datazone/speciesfactsheet.php?id=3 | title=Lesser Rhea Rhea pennata | access-date=15 June 2012 | author=BirdLife International | year=2012| work=Data Zone}}</ref>
 === Feral populations in Europe ===
-A small population of rheas has emerged in [[Mecklenburg-Western Pomerania]], northeastern [[Germany]], after several couples escaped from an exotic meat farm near [[Lübeck]] in the late 1990s. Contrary to expectations, the large birds adapted well to conditions in the German countryside.<ref>{{cite news| url=https://www.welt.de/wissenschaft/article5701264/Nandus-ein-tierisches-Einwanderungsproblem.html | date=2 January 2010 | access-date=5 November 2014 | last=Kulke | first=Ulli | language=de | title=Nandus - ein tierisches Einwanderungsproblem | trans-title=Rheas - an animal immigration problem | website=Die Welt}}</ref> A monitoring system has been in place since 2008.<ref>{{cite web | url=http://www.nandu.info/index.html | title=Informationen der Arbeitsgruppe Nandumonitoring | language=de | trans-title=Information of the rhea monitoring working group | access-date=5 November 2014}}</ref> By 2014, there was already a population of well over 100 birds in an area of {{convert|150|km2}} between the river [[Wakenitz]] and the [[Bundesautobahn 20|A20 motorway]], slowly expanding eastward.<ref>{{cite news| url=http://www.spiegel.de/wissenschaft/natur/tierische-einwanderer-nandus-breiten-sich-in-mecklenburg-vorpommern-aus-a-1001114.html|title=Mecklenburg-Vorpommern: Nandus vergrößern ihren Lebensraum weiter | access-date=5 November 2014 | newspaper=Der Spiegel | date=5 November 2014 | language=de | trans-title=Mecklenburg-Vorpommern: Rheas further extend their habitat}}</ref>
+A small population of rheas has emerged in [[Mecklenburg-Western Pomerania]], northeastern [[Germany]], after several couples escaped from an exotic meat farm near [[Lübeck]] in the late 1990s. Contrary to expectations, the large birds adapted well to conditions in the German countryside.<ref>{{cite news| url=https://www.welt.de/wissenschaft/article5701264/Nandus-ein-tierisches-Einwanderungsproblem.html | date=2 January 2010 | access-date=5 November 2014 | last=Kulke | first=Ulli | language=de | title=Nandus – ein tierisches Einwanderungsproblem | trans-title=Rheas – an animal immigration problem | website=Die Welt}}</ref> A monitoring system has been in place since 2008.<ref>{{cite web | url=http://www.nandu.info/index.html | title=Informationen der Arbeitsgruppe Nandumonitoring | language=de | trans-title=Information of the rhea monitoring working group | access-date=5 November 2014}}</ref> By 2014, there was already a population of well over 100 birds in an area of {{convert|150|km2}} between the river [[Wakenitz]] and the [[Bundesautobahn 20|A20 motorway]], slowly expanding eastward.<ref>{{cite news| url=http://www.spiegel.de/wissenschaft/natur/tierische-einwanderer-nandus-breiten-sich-in-mecklenburg-vorpommern-aus-a-1001114.html|title=Mecklenburg-Vorpommern: Nandus vergrößern ihren Lebensraum weiter | access-date=5 November 2014 | newspaper=Der Spiegel | date=5 November 2014 | language=de | trans-title=Mecklenburg-Vorpommern: Rheas further extend their habitat}}</ref>
 [[File:Greater rhea (Nandu), Lenschow.jpg|left|thumb|Feral greater rhea flock in Germany]]
-The population grew steadily for several years. By autumn 2018 their numbers had greatly increased to about 600. As such, local farmers claim increasing damage to their fields, and some biologists say the rheas pose a growing risk to local wildlife. Still protected by German natural conservation law, a local discussion has begun regarding how to handle the situation. Eventually, Mecklenburg-Western Pomerania's government allowed limited hunting of the birds, explicitly to just reduce the population's growth and not to wipe them out. At this point, it was generally agreed that the rheas should be allowed to stay in the region. By spring 2021, just 247 rheas were counted; this development was attributed to both the hunting as well as the increased caution of the animals. Several had begun to avoid humans more than previously, and retreated into the woods.<ref>{{cite web |last=Burghardt |first=Peter | url=https://www.sueddeutsche.de/politik/nandu-wolf-deutschland-1.5267749 |title=Nandus unter Beschuss | trans-title=Nandus under fire | website=Süddeutsche Zeitung | language=de | date=18 April 2021 | access-date=3 September 2021 }}</ref><ref>{{cite web | url=https://www.ndr.de/nachrichten/mecklenburg-vorpommern/Kontroverse-Nandu-Jagd-in-MV,nandujagd100.html |title=Kontroverse Nandu-Jagd in MV | trans-title=Controversial nandu hunt in MV | website=NDR | language=de | date=24 January 2021 | access-date=3 September 2021 }}</ref> Some members of this rhea population have also expanded into other areas; at least twice individual rheas who probably originated in Mecklenburg-Western Pomerania were sighted in [[Brandenburg]]'s [[High Fläming Nature Park]], over {{convert|200|km}} from their usual range.<ref>{{cite web | url=https://www.rbb24.de/panorama/beitrag/2021/08/nandu-maerkischer-strausse-mark-eva-loth-norbert-eschholz.html |title=Fotografin lichtet schnellen Nandu im Hohen Fläming ab | trans-title=Photographer takes a photo of a fast nandu in High Fläming | website=rbb24 | language=de | date=27 August 2021 | access-date=3 September 2021 }}</ref>
+The population grew steadily for several years. By autumn 2018, their numbers had significantly increased to about 600. As such, local farmers claim increasing damage to their fields, and some biologists say the rheas pose a growing risk to local wildlife. Still protected by German natural conservation law, a local discussion developed regarding how to handle the situation. Eventually, Mecklenburg-Western Pomerania's government allowed limited hunting of the birds, explicitly to just reduce the population's growth and not to wipe them out. At this point, it was generally agreed that the rheas should be allowed to stay in the region. By spring 2021, just 247 rheas were counted; this development was attributed to both the hunting and the increased caution of the animals. Several had begun to avoid humans more than previously and retreated into the woods.<ref>{{cite web |last=Burghardt |first=Peter | url=https://www.sueddeutsche.de/politik/nandu-wolf-deutschland-1.5267749 |title=Nandus unter Beschuss | trans-title=Nandus under fire | website=Süddeutsche Zeitung | language=de | date=18 April 2021 | access-date=3 September 2021 }}</ref><ref>{{cite web | url=https://www.ndr.de/nachrichten/mecklenburg-vorpommern/Kontroverse-Nandu-Jagd-in-MV,nandujagd100.html |title=Kontroverse Nandu-Jagd in MV | trans-title=Controversial nandu hunt in MV | website=NDR | language=de | date=24 January 2021 | access-date=3 September 2021 }}</ref> Some members of this rhea population have also expanded into other areas; at least twice individual rheas who probably originated in Mecklenburg-Western Pomerania were sighted in [[Brandenburg]]'s [[High Fläming Nature Park]], over {{convert|200|km}} from their usual range.<ref>{{cite web | url=https://www.rbb24.de/panorama/beitrag/2021/08/nandu-maerkischer-strausse-mark-eva-loth-norbert-eschholz.html |title=Fotografin lichtet schnellen Nandu im Hohen Fläming ab | trans-title=Photographer takes a photo of a fast nandu in High Fläming | website=rbb24 | language=de | date=27 August 2021 | access-date=3 September 2021 }}</ref> By early 2023, 91 rheas were counted in Mecklenburg-Western Pomerania; the population decline was attributed to both hunting as well as harsher weather of previous years. By this point, German authorities believed a stable population of 50 adult birds would be optimal for the local ecosystem and agriculture. Researchers concluded that the feral population was subject to substantial fluctuations but remained healthy, adaptable, and entrenched in the area.<ref>{{cite web | url=https://www.nationalgeographic.de/tiere/2023/08/wilde-nandus-in-deutschland-die-riesenvoegel-vom-schaalsee |title=Wilde Nandus in Deutschland: Die Riesenvögel vom Schaalsee | trans-title=Wild rheas in Germany: The great birds of Schaalsee | website=National Geographic | language=de | date=31 August 2023 | access-date=24 May 2024 }}</ref>
-There also appears to be a small population of wild rheas in the [[United Kingdom]]. In March 2021, a group of about 20 rheas were reported to be running free on a residential estate in [[Hertfordshire]]. Local police were unable to identify any owner, so the assumption was that they were wild birds. Once caught, authorities intend to place them in a suitable nature reserve to allow them to develop as a colony.<ref>{{Cite web|last=BBC News|date=2021-03-26|title=Rhea birds running wild on Hertfordshire housing estate.|url=https://www.bbc.co.uk/news/uk-england-beds-bucks-herts-56535979|url-status=live|access-date=2021-03-26|website=BBC News}}</ref>
+There also appears to be a small population of wild rheas in the [[United Kingdom]]. In March 2021, about 20 rheas were reportedly running free on a residential estate in [[Hertfordshire]]. Local police could not identify any owner, so they assumed they were wild birds. Once caught, authorities intend to place them in a suitable nature reserve to allow them to develop as a colony.<ref>{{Cite web|last=BBC News|date=2021-03-26|title=Rhea birds running wild on Hertfordshire housing estate.|url=https://www.bbc.co.uk/news/uk-england-beds-bucks-herts-56535979|access-date=2021-03-26|website=BBC News}}</ref>
 ==Behavior==
@@ Line 87: / Line 116: @@
 ===Individual and flocking===
-Rheas tend to be silent birds, with the exception being when they are chicks or when the male is seeking a mate. During breeding season, the male will attempt to attract females by calling. This call is a loud booming noise. While calling like this, they will lift the front of their body, ruffle their plumage, all while keeping their neck stiff. They will then extend and raise their wings, and run short distances, alternating with their wings. He may then single out a female and walk alongside or in front of her with a lowered head and spread wings. If the female notices him, then he will wave his neck back and forth in a figure eight. Finally, a female may offer herself and copulation will commence.<ref name="Davies"/>
+Rheas tend to be silent birds, except when they are chicks or the male seeks a mate. During the breeding season, the male will attempt to attract females by calling. This call is a loud booming noise. While calling like this, they will lift the front of their body and ruffle their plumage, all while keeping their neck stiff. They will then extend and raise their wings and run short distances, alternating with their wings. He may then single out a female and walk alongside or in front of her with a lowered head and spread wings. If the female notices him, he will wave his neck back and forth in a figure eight. Finally, a female may offer herself, and copulation will commence.<ref name="Davies"/>
-During the non-breeding season they may form flocks of between 20 and 25 birds,<ref name=Coomber>{{cite book|last=Coomber|first=Richard|title=Birds of the World|year=1991|publisher=Colour Library Books Ltd.|location=Godalming, Surrey|isbn=0862838061|pages=[https://archive.org/details/photographicency0000coom/page/8 8–9]|editor=Gill Waugh|chapter=Rheiformes: Rheas|chapter-url=https://archive.org/details/photographicency0000coom/page/8}}</ref> although the lesser rhea forms smaller flocks than this. When in danger they flee in a [[zigzag]] course, using first one wing then the other, similar to a rudder. During breeding season the flocks break up.<ref name="Davies"/>
+During the non-breeding season they may form flocks of between 20 and 25 birds,<ref name=Coomber>{{cite book|last=Coomber|first=Richard|title=Birds of the World|year=1991|publisher=Colour Library Books Ltd.|location=Godalming, Surrey|isbn=0862838061|pages=[https://archive.org/details/photographicency0000coom/page/8 8–9]|editor=Gill Waugh|chapter=Rheiformes: Rheas|chapter-url=https://archive.org/details/photographicency0000coom/page/8}}</ref> although the lesser rhea forms smaller flocks than this. When in danger, they flee in a [[zigzag]] course, using one wing and the other, similar to a rudder. During the breeding season, the flocks break up.<ref name="Davies"/>
 ===Diet===
-For the most part, rheas are herbivorous and prefer broad-leafed plants but they also eat fruits, seeds and roots, as well as insects such as grasshoppers and small reptiles and rodents.<ref name=Davies/> Young rheas generally eat only insects for the first few days. Outside of the breeding season they gather in flocks and feed with deer and cattle.<ref name=Coomber/>
+Mostly, rheas are herbivorous and prefer broad-leafed plants, but they also eat fruits, seeds, roots, and insects such as grasshoppers, small reptiles, and rodents.<ref name=Davies/> Young rheas eat only insects for the first few days. Outside the breeding season, they gather in flocks and feed with deer and cattle.<ref name=Coomber/>
 ===Reproduction===
-Rheas are polygamous, with males courting between two and twelve females. After mating, the male builds a nest, in which each female lays her eggs in turn. The nest consists of a simple scrape in the ground, lined with grass and leaves.<ref name=EoB/> The male incubates from ten to sixty eggs. The male will use a decoy system and place some eggs outside the nest and sacrifice these to predators, so that they do not attempt to get inside the nest. The male may use another subordinate male to incubate his eggs, while he finds another harem to start a second nest.<ref name="Davies"/> The chicks hatch within 36 hours of each other. Right before hatching, the chicks begin to whistle.<ref>{{Cite web|date=2020-01-27|title=Listen: Greater Rhea Nests Are Filled With Dozens of Whistling Eggs|url=https://www.audubon.org/news/listen-greater-rhea-nests-are-filled-dozens-whistling-eggs|access-date=2022-01-26|website=Audubon|language=en}}</ref> The females, meanwhile, may move on and mate with other males. While caring for the young, the males will charge at any perceived threat that approach the chicks including female rheas and humans. The young reach full adult size in about six months but do not breed until they reach two years of age.<ref name="EoB"/>
+Rheas are polygynandrous, with males courting between two and twelve females and females commonly mating with multiple dominant males during the breeding season. After mating, the male builds a nest where each female lays eggs. The nest is a simple scrape in the ground, lined with grass and leaves.<ref name=EoB/> The male incubates from ten to sixty eggs. The male will use a decoy system and place some eggs outside the nest, then sacrifice these to predators so they do not attempt to get inside the nest. The male may use another subordinate male to incubate his eggs while he finds another group of females to start a second nest with.<ref name="Davies"/> The chicks hatch within 36 hours of each other. Right before hatching, the chicks begin to whistle.<ref>{{Cite web|date=2020-01-27|title=Listen: Greater Rhea Nests Are Filled With Dozens of Whistling Eggs|url=https://www.audubon.org/news/listen-greater-rhea-nests-are-filled-dozens-whistling-eggs|access-date=2022-01-26|website=Audubon|language=en}}</ref> The group of females, meanwhile, may move on and mate with other males. While caring for the young, the males will charge at any perceived threat approaching the chicks, including female rheas and humans. The young reach full adult size in about six months but do not breed until they reach two years of age.<ref name="EoB"/>
 ==Status and conservation==
-The numbers of both the greater and puna rhea are decreasing as their habitats are shrinking. Both are considered [[near threatened]] by the IUCN. The IUCN also states that they are both approaching [[Vulnerable species|vulnerable]] status.<ref name="IUCN_tarapacensis"/><ref name=BLI/><ref name=BLI1/><ref name="IUCN_americana">{{cite iucn | author = BirdLife International | authorlink = BirdLife International | title = ''Rhea americana'' | volume= 2016 | page = e.T22678073A92754472 | year = 2016 | doi = 10.2305/IUCN.UK.2016-3.RLTS.T22678073A92754472.en }}</ref> The lesser rhea is classified as [[least concern]].<ref name="IUCN_pennata">{{cite iucn | author = BirdLife International | authorlink = BirdLife International | title = ''Rhea pennata'' | volume = 2016 | page = e.T22728199A94974489 | year = 2016 | doi = 10.2305/IUCN.UK.2016-3.RLTS.T22728199A94974489.en }}</ref>
+The numbers of the greater and puna rhea are decreasing as their habitats shrink. Both are considered [[near threatened]] by the IUCN. The IUCN also states that they are both approaching [[Vulnerable species|vulnerable]] status.<ref name="IUCN_tarapacensis">{{cite iucn | author = BirdLife International | authorlink = BirdLife International | title = ''Rhea tarapacensis'' | volume = 2016 | page = e.T22728206A94974751 | year = 2016 | doi = 10.2305/IUCN.UK.2016-3.RLTS.T22728206A94974751.en }}</ref><ref name=BLI/><ref name=BLI1/><ref name="IUCN_americana">{{cite iucn | author = BirdLife International | authorlink = BirdLife International | title = ''Rhea americana'' | volume= 2016 | page = e.T22678073A92754472 | year = 2016 | doi = 10.2305/IUCN.UK.2016-3.RLTS.T22678073A92754472.en }}</ref> The lesser rhea is classified as [[least concern]].<ref name="IUCN_pennata">{{cite iucn | author = BirdLife International | authorlink = BirdLife International | title = ''Rhea pennata'' | volume = 2016 | page = e.T22728199A94974489 | year = 2016 | doi = 10.2305/IUCN.UK.2016-3.RLTS.T22728199A94974489.en }}</ref>
 ==Human interaction==
@@ Line 121: / Line 150: @@
 {{Palaeognathae|N.}}
+{{Meat}}
 {{Portal bar|Birds|Animals}}
 {{Taxonbar|from=Q19171}}