A family of Rhea pennata pennatas in the wild in Chile, 2006Head of a Darwin's rhea at the Edinburgh Zoo
The lesser rhea stands at 90to 100cm (35–39in) tall. Length is 92to 100cm (36–39in) and weight is 15to 28.6kg (33–63lb).[6][7] Like most ratites, it has a small head and a small bill, the latter measuring 6.2 to 9.2cm (2.4 to 3.6in), but has long legs and a long neck. It has relatively larger wings than other ratites, enabling it to run particularly well. It can reach speeds of 60km/h (37mph), enabling it to outrun predators. The sharp claws on the toes are effective weapons. Their feathers are similar to those of ostriches, in that they have no aftershaft.[8] Their plumage is spotted brown and white, and the upper part of their tarsus is feathered.[6] The tarsus is 28 to 32cm (11 to 13in) long and has 18 horizontal plates on the front.[6]
Etymology
It is known as ñandú petiso, or ñandú del norte, in Argentina, where the majority live. Other names are suri and choique. The name ñandú comes from the greater rhea's name in Guaraní, ñandu guazu, meaning big spider, possibly in relation to their habit of alternately opening and lowering their wings when they run. In English, Darwin's rhea gets its scientific name from Rhea, a Greek goddess, and pennata, meaning winged. The specific name was bestowed in 1834 by Darwin's contemporary and rival Alcide d'Orbigny, who first described the bird to Europeans from a specimen from the lower Río Negro south of Buenos Aires, Argentina.[6][9] As late as 2008, it was classified in the monotypic genus Pterocnemia. This word is formed from two Greek words pteron, meaning feathers, and knēmē, meaning the leg between the knee and the ankle, hence feather-legged, alluding to their feathers that cover the top part of the leg.[10] In 2008, the SACC subsumed Pterocnemia into the genus Rhea.[11]
Taxonomy
Three subspecies have traditionally been recognized:
The IUCN considers the former two northern taxaR. p. tarapacensis and R. p. garleppi as a separate species, the puna rhea (R. tarapacensis).[14][13] Both garleppi and tarapacensis were described by Charles Chubb in 1913.[3] It is possible garleppi should be considered a junior synonym of tarapacensis.
Behavior
The lesser rhea is mainly a herbivore, with the odd small animal (lizards, beetles, grasshoppers) eaten on occasion. It predominately eats saltbush and fruits from cacti, as well as grasses, roots, seeds, and leaves.[6][15] They tend to be quiet birds, except as chicks when they whistle mournfully, and as males looking for a female, when they emit a booming call.[6]
The males of this species become aggressive once they are incubating eggs, even towards females. The females thus lay the later eggs near the nest, rather than in it. Most of the eggs are moved into the nest by the male, but some remain outside, where they rot and attract flies. The male, and later the chicks, eat these flies. The incubation period is 30–44days, and the clutch size is from 5–55 eggs. The eggs are 87to 126mm (3.4–5.0in) and are greenish yellow.[6] Chicks mature by three years of age. Outside the breeding season, Darwin's rhea is quite sociable: it lives in groups of from 5 to 30 birds, of both sexes and a variety of ages.[6]
Distribution and habitat
Darwin's rhea lives in areas of open scrub in the grasslands of Patagonia and on the Andean plateau (the Altiplano), through the countries of Argentina, Bolivia, Chile, and Peru.[1] All subspecies prefer grasslands, brushlands and marshland. However, the nominate subspecies prefers elevations less than 1,500m (4,900ft),[1] where the other subspecies typically range from 3,000to 4,500m (9,800–14,800ft), but locally down to 1,220m (4,000ft) in the south.[14]
History of the discovery of the genus Rhea
Illustration of Darwin's rhea, published in 1841 in John Gould's description of birds collected on the second voyage of HMS Beagle
During the second voyage of HMS Beagle, the young naturalist Charles Darwin made many trips on land, and around August 1833 heard from gauchos in the Río Negro area of Northern Patagonia about the existence of a smaller rhea, "a very rare bird which they called the Avestruz Petise". He continued searching fruitlessly for this bird, and the Beagle sailed south, putting in at Port Desire in southern Patagonia on 23 December. On the following day, Darwin shot a guanaco (similar to a llama) which provided them with a Christmas meal, and in the first days of January, the artist Conrad Martens shot a rhea which they enjoyed eating before Darwin realised that this was the elusive smaller rhea rather than a juvenile, and preserved the head, neck, legs, one wing, and many of the larger feathers. As with his other collections, these were sent to John Stevens Henslow in Cambridge. On 26 January the Beagle entered the Straits of Magellan, and at St Gregory's Bay Darwin met Patagonians he described as "excellent practical naturalists". A half Indian, who had been born in the Northern Provinces, told him that the smaller rheas were the only species this far south, while the larger rheas kept to the north. On an expedition up the Santa Cruz River, they saw several of the smaller rheas, which were too wary to be approached closely or caught.[16][17]
In 1837, Darwin's rhea was described as Rhea darwinii (later synonymized with R. pennata) by the ornithologist John Gould in a presentation to the Zoological Society of London, in which he was followed by Darwin reading a paper on the eggs and distribution of the two species of rheas.[18]
When Gould classified Darwin's rhea and the greater rhea as separate species, he confirmed a serious problem for Darwin. These birds mainly live in different parts of Patagonia, but there is also an overlapping zone where the two species coexist. As every living being had been created in a fixed form, as accepted by the science of his time, they could only change their appearance by a perfect adaptation to their way of life, but would still be the same species. But now he had to deal with two different species. This started to form his idea that species were not fixed at all, but that another mechanism might be at work.[19]
Darwin's rhea is categorized as least concern by the IUCN.[1] The former southern nominate subspecies remains relatively widespread and locally fairly common. Its range is estimated at 859,000km2 (332,000sqmi).[1] The situation for the two former northern subspecies is more worrying, with their combined population estimated as being possibly as low as in the hundreds.[14] However, they are classified as Rhea tarapacensis by the IUCN, which regards it as being near threatened, with the primary threats being hunting, egg-collecting, and fragmentation of its habitat due to conversion to farmland or pastures for cattle-grazing.[14][6]
↑ Pterocnemia pennata pennata is included in Appendix II.
Related Research Articles
Rheas, also known as ñandus or South American ostrich, are moderately-sized South American ratites of the order Rheiformes. They are distantly related to the African ostriches and Australia’s emu, with rheas placing just behind the emu in height and overall size.
Tinamous form an order of birds called Tinamiformes, comprising a single family called Tinamidae, divided into two distinct subfamilies, containing 46 species found in Mexico, Central America, and South America. The word "tinamou" comes from the Galibi term for these birds, tinamu. Tinamous have traditionally been regarded as the sister group of the flightless ratites, but recent work places them well within the ratite radiation, implying basal ratites could fly. Tinamous first appear in the fossil record in the Miocene epoch. They are generally sedentary, ground-dwelling and, though not flightless, when possible avoid flight in favour of hiding or running away from danger. They are found in a variety of habitats, ranging from semi-arid alpine grasslands to tropical rainforests. The two subfamilies are broadly divided by habitat, with the Nothurinae referred to as steppe or open country tinamous, and the Tinaminae known as forest tinamous.
Diplolaemus is a genus of lizards in the family Leiosauridae. The genus is endemic to southern South America.
Flightless birds are birds that, through evolution, lost the ability to fly. There are over 60 extant species, including the well-known ratites and penguins. The smallest flightless bird is the Inaccessible Island rail. The largest flightless bird, which is also the largest living bird in general, is the ostrich.
The Puna teal is a species of dabbling duck in the family Anatidae. It was at one time regarded as a subspecies of the silver teal.
Darwin’s frog, also called the Southern Darwin's frog, is a species of Chilean/Argentinian frog of the family Rhinodermatidae. It was discovered by Charles Darwin during his voyage on HMS Beagle. on a trip to Chile. In 1841, French zoologist André Marie Constant Duméril and his assistant Gabriel Bibron described and named Darwin's frog. The diet of R. darwinii consists mostly of herbivore invertebrates. R. darwinii is currently classified as an endangered species by the International Union for Conservation of Nature.
The greater rhea is a species of flightless bird native to eastern South America. Other names for the greater rhea include the grey, common, or American rhea; ema (Portuguese); or ñandú. One of two species in the genus Rhea, in the family Rheidae, it inhabits a variety of open areas, such as grasslands, savanna or grassy wetlands. Weighing 20–27 kilograms (44–60 lb), the greater rhea is the largest native bird in the Americas. In the wild, the greater rhea has a life expectancy of 10.5 years. It is also notable for its reproductive habits, and for the fact that a population has established itself in Northern Germany in recent years. The species is listed as Near Threatened by the IUCN.
The puna tinamou also known as Pentland's tinamou, is a member of the most ancient groups of bird families, the tinamous. This species is native to southern South America. The binomial name of the species commemorates the Irish natural scientist Joseph Barclay Pentland (1797–1873) by Nicholas Aylward Vigors in 1837. The IUCN list this species as Least Concern, with an occurrence range of 590,000 km2 (230,000 sq mi).
The ornate tinamou is a type of tinamou commonly found in the high altitude grassland and dry shrubland in subtropical and tropical regions of west central South America.
The Chilean tinamou is a type of tinamou commonly found in high elevation shrubland in subtropical regions of central Chile.
Darwin's nothura is a type of tinamou commonly found in high-altitude grassland in the southern Andes in South America.
The quebracho crested tinamou is a species of tinamou found in dry forest habitats in Paraguay and northern Argentina in South America.
The huayco tinamou, also known as waypu (Quechua), is a species of bird found on grassy mountain ridges in the Andes of Bolivia and Argentina.
The rufous-tailed hawk is a species of bird of prey in the family Accipitridae.
Nothura is a genus of birds in the tinamou family. This genus comprises five members of this South American family.
R. darwinii may refer to:
P. darwinii may refer to:
Commemoration of Charles Darwin began with geographical features named after Darwin while he was still on the Beagle survey voyage, continued after his return with the naming of species he had collected, and extended further with his increasing fame. Many geographical features, species and institutions bear his name. Interest in his work has led to scholarship and publications, nicknamed the Darwin Industry, and his life is remembered in fiction, film and TV productions as well as in numerous biographies. Darwin Day has become an annual event, and in 2009 there were worldwide celebrations to mark the bicentenary of Darwin's birth and the 150th anniversary of the publication of On the Origin of Species.
Rheiformes is an order that contains the family Rheidae (rheas). It is in the infraclass Paleognathae, which contains all ratites. Extant members are found in South America. While the IOC World Bird List and the Clements Checklist categorise Rheiformes as its own order, the BirdLife Data Zone includes rheas, along with ostriches, tinamous, cassowaries, emu, and kiwis, in the order Struthioniformes. Of the two extant species of rheas recognized by the IUCN Red List, as of 2022, Rhea americana is listed as near threatened, while Rhea pennata is listed as least concern. From 2014 to 2022, the IUCN recognised Rhea tarapacensis as a separate species, and listed it as near threatened in its last assessment in 2020; in 2022, it was again recognised as a subspecies of R. pennata.
References
Wikimedia Commons has media related to Rhea pennata.
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 (2nded.). Farmington Hills, MI: Gale Group. pp.69–74. ISBN0-7876-5784-0.
Elliott, Andrew (1992). "Lesser Rhea". In Hoyo, Joseph del (ed.). Handbook of the Birds of the World. Vol.1 (Ostrich to Ducks). Lynx Edicions. ISBN978-8487334108.
Gotch, A.F. (1995) [1979]. "15". Latin Names Explained. A Guide to the Scientific Classifications of Reptiles, Birds & Mammals. London: Facts on File. p.176. ISBN0-8160-3377-3.
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