Journal of Ornithology

, 150:127 | Cite as

Reproductive success of wild Lesser Rheas (Pterocnemia -Rhea- pennata pennata) in north-western Patagonia, Argentina

  • Fernando R. BarriEmail author
  • Monica B. Martella
  • Joaquín L. Navarro
Original Article


We studied the reproductive success of a wild Lesser Rhea population (Pterocnemia -Rhea- pennata pennata) during two reproductive seasons (2004/2005 and 2005/2006) in north-western Patagonia, Argentina. The parameters recorded included population and nest density, clutch size, hatching success, chick survival (up to 3 months of age) and percentage of chicks that reached the juvenile stage after the winter. We also estimated the percentage of males that attempted to nest and of those that were successful (those producing at least one chick), daily nest mortality rates (DNMR) at different stages of the nesting cycle and the probability that an egg that has been recently laid will produce a chick. On average, both years pooled, the density of this population of Lesser Rheas was 1.55 ± 0.2 individuals/km2 (SE), nest density was 0.17 ± 0.04 per km 2 , clutch size was 20.8 ± 6.4 eggs, hatching success was 74.4% ± 11.3, Mayfield’s probability of an egg that will produce a chick was 0.64, chick survival was 65.4% ± 14.5 and percentage of chicks that reached the juvenile stage was 26.3%. Nearly a quarter of Lesser Rhea males in the population attempted to nest during a breeding season, and the DNMR was significantly higher during the laying stage (most nest failures were due to anthropogenic disturbances related to livestock raising activities). Nesting success, hatching success, and chick survival of Lesser Rheas were higher than those of their most closely related species, the Greater Rhea (Rhea americana), whereas the percentage of chicks that reached the juvenile stage was similar due to high winter mortalities of chicks. We suggest that the increase in reproductive effort is a strategy of this species to overcome environmental constraints.


Conservation Lesser Rhea Reproductive success 



We are grateful to E. Domingo, current Director of EEA INTA Bariloche, for allowing us to work at Pilcanyeu experimental field. N. Roldán, J. Von Thüngen, D. Sarasqueta and the personnel at Pilcaniyeu collaborated during the fieldwork. I. Rehm translated the abstract into German. Financial support was provided by Secretaría de Ciencia y Técnica of Universidad Nacional de Córdoba, and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). F.R.B. is a fellow and M.B.M. and J.L.N. are researchers of CONICET.


  1. Barri FR, Martella MB, Navarro JL (2008) Effects of hunting, egg harvest and livestock grazing intensities on density and reproductive success of Lesser Rhea Pterocenemia -Rhea- pennata pennata in Patagonia: implications for conservation. Oryx.
  2. Balmford A (1992) Poliandria y cuidado uniparental de machos en el ñandú petiso. Informe para Corporación Nacional Forestal de Chile, Cambridge, UKGoogle Scholar
  3. Bellis LM, Martella MB, Navarro JL, Vignolo P (2004) Home range of greater and Lesser Rhea in Argentina: relevance to conservation. Biodivers Conserv 13(14):2589–2598. doi: 10.1007/s10531-004-1086-0 CrossRefGoogle Scholar
  4. Bertram BC (1992) The Ostrich communal nesting system. Princeton University Press, PrincetonGoogle Scholar
  5. Clutton-Brock TH (ed) (1988) Introduction. In: Reproductive success: studies of individual variation in contrasting breeding systems, The University of Chicago Press, Chicago, pp 1–6Google Scholar
  6. Delsuc F, Superina M, Ferraris G, Tilak M, Douzery E (2007) Molecular evidence for hybridization between the two living species of South American ratites: potential conservation implications. J Cons Gen 8(2):503–507. doi: 10.1007/s10592-006-9179-9 CrossRefGoogle Scholar
  7. Fernández GJ, Reboreda JC (1998) Effects of clutch size and timing of breeding on reproductive success of greater rheas. Auk 115(2):602–607Google Scholar
  8. Fernández GJ, Reboreda JC (2000) Egg losses and nest desertion in greater rheas (Rhea americana). Ibis 142:29–34. doi: 10.1111/j.1474-919X.2000.tb07680.x CrossRefGoogle Scholar
  9. Fernández GJ, Reboreda JC (2002) Nest-site selection by male greater rheas. J Field Ornithol 73(2):166–173Google Scholar
  10. Fernández GJ, Reboreda JC (2003) Male parental care in greater rheas (Rhea americana) in Argentina. Auk 120(2):418–428. doi: 10.1642/0004-8038(2003)120[0418:MPCIGR]2.0.CO;2 CrossRefGoogle Scholar
  11. Fernández GJ, Reboreda JC (2007) Cost of large communal clutches for male and female Greater Rheas (Rhea americana). Ibis 149(2):215–222. doi: 10.1111/j.1474-919X.2006.00629.x CrossRefGoogle Scholar
  12. Folch A (1992) Family Rheidae (Rheas). In: Del Hoyo J, Elliott A, Sargatal J (eds) Handbook of the birds of the world, vol 1: ostrich to ducks. Lynx, Barcelona, pp 83–84Google Scholar
  13. Hanford PT, Mares MA (1985) The mating systems of Ratites and Tinamous: an evolutionary perspective. Biol J Linn Soc 25:77–104. doi: 10.1111/j.1095-8312.1985.tb00387.x CrossRefGoogle Scholar
  14. International Union for Conservation of Nature (IUCN) (2007) 2007 IUCN Red list of threatened species. IUCN. Gland, Switzerland. Available at: Accessed 7 Sept 2007
  15. Johnson DH (1979) Estimating nest success: the Mayfield method and an alternative. Auk 96:651–661Google Scholar
  16. Lores R, Ferreira C, Montana C, Anchorena J, Marcolin A (1982) Estudio y clasificación de la vegetación del campo experimental Pilcaniyeu (R. Negro): su relación con el ambiente. Memoria Técnica. Volumen 6. Estación Experimental Agropecuaria INTA Bariloche, ArgentinaGoogle Scholar
  17. Martin TE (2004) Avian life-history evolution has an eminent past: does it have a bright future? Auk 121(2):289–301. doi: 10.1642/0004-8038(2004)121[0289:ALEHAE]2.0.CO;2 CrossRefGoogle Scholar
  18. Mayfield H (1975) Suggestions for calculating nest success. Wilson Bull 87:456–466Google Scholar
  19. Martella MB, Navarro JL (2002) Reproductivity and raising of Greater Rhea (Rhea americana) and Lesser Rhea (Pterocnemia pennata)—a review. Arch Geflugelkd 66:124–132Google Scholar
  20. Moore LA (2007) Population ecology of the southern cassowary Casuarius casuarius johnsonii, Mission Beach north Queensland. J Ornithol 148(3):357–366. doi: 10.1007/s10336-007-0137-1 CrossRefGoogle Scholar
  21. Navarro JL, Martella MB (2006) Conservación y Manejo de Ñandúes (Rhea americana y Rhea pennata). In: Bolkovic M, Ramadori E (eds) Manejo de Fauna Silvestre en Argentina, Programa de Uso Sustentable. Secretaria de Ambiente y Desarrollo Sustentable de la Nación, Buenos Aires, pp 39–50Google Scholar
  22. Navarro JL, Cardón R, Manero A, Clarke R (1999) Estimación de la abundancia poblacional de choique en vida silvestre. In: Secretaría de Recursos Naturales y Desarrollo Sustentable (ed) Informe a la dirección de Fauna y Flora Silvestres. Secretaría de Recursos Naturales y Desarrollo Sustentable, Buenos Aires, pp 18–19Google Scholar
  23. Navarro JL, Bellis LM, Lábaque C, Martella MB (2000) Crecimiento de pichones de choiques en criaderos: implicancias en el consumo y costos de alimentación. In: Robles C, Navarro J (eds) Conservación y Manejo del Choique en Patagonia. E.E.A. INTA Bariloche, Bariloche, pp 5–11Google Scholar
  24. Navarro JL, Vingolo PE, Demaría MR, Maceira NO, Martella MB (2005) Growth curves of farmed Greater Rheas (Rhea americana albescens) from central Argentina. Arch Geflugelkd 69(2):90–93Google Scholar
  25. Novaro AJ, Funes MC, Walker R (2000) Ecological extinction of native prey of carnivore assemblage in Argentine Patagonia. Biol Conserv 92:25–33. doi: 10.1016/S0006-3207(99)00065-8 CrossRefGoogle Scholar
  26. Pople A, Cairns SC, Grigg G (1991) Distribution and abundance of Emus (Dromaius novaehollandiae) in relation to the environment in the South Australian pastoral zone. Emu 91:222–229Google Scholar
  27. Sales J (2006) The Rhea, a ratite native to South America. Avian Poult Biol Rev 17(4):105–124CrossRefGoogle Scholar
  28. Sarasqueta DV (1990) Observaciones sobre la biología del Choique o Ñandú petiso de la Patagonia. Presencia 3(15):17–22Google Scholar
  29. Sarasqueta DV (2003) Cría y reproducción de Choiques en cautiverio. In: Real Escuela de Avicultura (ed) Cría de Avestruces, Emúes y Ñandúes, Real Escuela de Avicultura, Barcelona, pp 327–363Google Scholar
  30. Sarasqueta DV (2005) Aspects of rearing, reproduction and hybridization of Darwin’s Rhea or Choique (Rhea pennata syn. Pterocnemia pennata, spp pennata). In: Carbajo Garcia E (ed) Proc Int Ratite Sci Symp. Madrid, Spain, pp 35–44Google Scholar
  31. Sibley CG, Ahlquist JE (1990) Ratites and Tinamous. In: Phylogeny and classification of birds. A study in molecular evolution. Yale University Press, London, pp 273–288Google Scholar
  32. Soriano A, Sala O (1983) Ecological strategies in a Patagonian arid steppe. J Plant Ecol 56(1):9–15. doi: 10.1007/BF00036131 CrossRefGoogle Scholar
  33. Sutherland WJ, Newton I, Green RE (2004) Bird ecology and conservation. Oxford University press, OxfordGoogle Scholar
  34. Temple SA, Fevold BM, Paine LK, Undersander DJ, Sample DW (1999) Nesting birds and grazing cattle: accommodating both on Midwestern pastures. Stud Avian Biol 19:196–202Google Scholar
  35. Thomas L, Laake JL, Derry JF, Buckland ST, Borchers DL, Anderson DR et al (2001) Distance 4.0. Beta 1. Research unit for wildlife population assessment, University of St. Andrews, UK. Available at: Accessed 12 Jan 2007

Copyright information

© Dt. Ornithologen-Gesellschaft e.V. 2008

Authors and Affiliations

  • Fernando R. Barri
    • 1
    Email author
  • Monica B. Martella
    • 1
  • Joaquín L. Navarro
    • 1
  1. 1.Centro de Zoología AplicadaUniversidad Nacional de CórdobaCordobaArgentina

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