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Greater Rhea Rhea americana

This species qualifies as Near Threatened as its population is believed to have declined at a rate approaching the threshold for classification as Vulnerable.

Taxonomic source(s)
SACC. 2006. A classification of the bird species of South America. Available at:
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.
Stotz, D. F.; Fitzpatrick, J. W.; Parker, T. A.; Moskovits, D. K. 1996. Neotropical birds: ecology and conservation. University of Chicago Press, Chicago.

Distribution and population
Rhea americana has a large range in north-east and south-east Brazil, east Bolivia, Paraguay, Uruguay and north-east and east Argentina south to 40°S (Folch 1992). It has declined markedly and the healthiest populations are now believed to be in parts of the Chaco region (Folch 1992).

Population justification
The global population size has not been quantified, but this species is described as 'uncommon to fairly common' (Stotz et al. 1996).

Trend justification
A moderately rapid and on-going population decline is suspected, owing to hunting for the species's skin and meat as well as the destruction and fragmentation of its habitat.

It typically occurs in pampas, campo cerrado and open chaco woodland, normally in areas with some tall grassland and other vegetation, but also in open grassland and cultivated fields, at elevations up to 1,200 m (Canevari et al. 1991, Folch 1992, Sick 1993, Parker et al. 1996). Population densities in grassland are several times that in agricultural areas, and birds were found to occupy 51% of a grassland area, but less than 5% of an agricultural locality (Giordano et al. 2008).  For breeding, it prefers areas adjacent to rivers, lakes and marshes (Folch 1992).

Its status is obfuscated by the presence of feral birds (Lowen et al. 1996), but it has declined markedly partly owing to hunting for meat and the colossal export of skins. Over 50,000 skins were traded in 1980, most apparently originating in Paraguay, with Japan and USA leading consumers (Folch 1992). In recent years, the large-scale conversion of central South American grasslands for agriculture and cattle-ranching (da Silva 1995) has considerably reduced and fragmented its available habitat, particularly in the pampas and cerrado strongholds.

Conservation Actions Underway
CITES Appendix II Conservation Actions Proposed
Monitor levels of illegal domestic and international trade. Effectively enforce restrictions on hunting and trade (Bellis et al. 2004). Include pastures and grasslands in agricultural ecosystems (Bellis et al. 2004). Preserve remaining natural habitat (Bellis et al. 2008, Giordano et al. 2010).

Related state of the world's birds case studies

Bellis, L, Martella M. B. and Navarro J. L. 2004. Habitat use by wild and captive-reared greater rheas Rhea americana in agricultural landscapes in Argentina. Oryx 38(3): 304-310.

Canevari, M. 1991. Nueva guia de las aves Argentinas. Fundación Acindar, Buenos Aires.

da Silva, J. M. C. 1995. Birds of the Cerrado Region, South America. Steenstrupia 21: 69-92.

Folch, A. 1992. Rheidai (Rheas). In: del Hoyo, J.; Elliott, A.; Sargatal, J. (ed.), Handbook of the birds of the world, pp. 84-89. Lynx Edicions, Barcelona, Spain.

Giordano, P. F.; Bellis, L. M.; Navarro, J. L.; Martella, M. B. 2008. Abundance and spatial distribution of Greater Rhea Rhea americana in two sites on the pampas grasslands with different land use. Bird Conservation International 18(1): 63-70.

Giordano, P. F.; Navarro, J. L.; Martella, M. B. 2010. Building large-scale spatially explicit models to predict the distribution of suitable habitat patches for the Greater Rhea (Rhea americana), a Near-threatened species. Biological Conservation 143: 357-365.

Lowen, J. C.; Bartrina, L.; Clay, R. P.; Tobias, J. A. 1996. Biological surveys and conservation priorities in eastern Paraguay (the final reports of Projects Canopy '92 and Yacutinga '95). CSB Conservation, Cambridge, U.K.

Parker, T. A.; Stotz, D. F.; Fitzpatrick, J. W. 1996. Ecological and distributional databases. In: Stotz, D.F.; Fitzpatrick, J.W.; Parker, T.A.; Moskovits, D.K. (ed.), Neotropical bird ecology and conservation, pp. 113-436. University of Chicago Press, Chicago.

Sick, H. 1993. Birds in Brazil: a natural history. Princeton University Press, Princeton.

Stotz, D. F.; Fitzpatrick, J. W.; Parker, T. A.; Moskovits, D. K. 1996. Neotropical birds: ecology and conservation. University of Chicago Press, Chicago.

Text account compilers
Symes, A., Benstead, P., Capper, D., Symes, A., Sharpe, C J

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2014) Species factsheet: Rhea americana. Downloaded from on 18/04/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from on 18/04/2014.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Greater rhea (Rhea americana) 0

Key facts
Current IUCN Red List category Near Threatened
Family Rheidae (Rheas)
Species name author (Linnaeus, 1758)
Population size Unknown mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 6,540,000 km2
Country endemic? No
Links to further information
- Additional Information on this species