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Journal of Ornithology

, Volume 149, Issue 2, pp 285–288 | Cite as

Characteristics, abundance and fertility of orphan eggs of the Lesser Rhea (Pterocnemia-Rhea-pennata pennata): implications for conservation

  • Fernando R. BarriEmail author
  • Mónica B. Martella
  • Joaquín L. Navarro
Short Note

Abstract

The Lesser Rhea (Pterocnemia-Rhea-pennata pennata) has a complex reproductive system that combines polygyny with sequential polyandry, in which males build the nest, fully incubate the eggs and care for the young. As occurs with the Greater Rhea (Rhea americana), Lesser Rhea females sporadically lay eggs outside the nest (‘orphan’ eggs), which are not incubated and thus fail to hatch. We have examined the orphan eggs of Lesser Rhea over two separate breeding seasons to determine their abundance and fertility status. During 2004 and 2005, weekly ground searches for orphan eggs were conducted in a wild population of Lesser Rhea in northwestern Patagonia, Argentina. During these searches the total number of nests, eggs in each nest and orphan eggs laid outside the nests was recorded. Orphan eggs represented approximately 7% of the total eggs laid in a breeding season. Six fresh orphan eggs were artificially incubated, four of them being fertile. Orphan eggs seemed to have two origins: some were laid near deserted nests in the early to mid-reproductive season; others were probably laid by first-time breeders and were found later in the reproductive season. Given the near-threatened status of the Lesser Rhea, harvesting and artificial incubation of orphan eggs, which otherwise would be unproductive, may contribute significantly to the conservation of this species, i.e., ‘recovered’ birds could be used for reintroduction or reinforcement of wild Lesser Rhea populations.

Keywords

Conservation Eggs Management Lesser Rhea Reproduction 

Notes

Acknowledgments

We are grateful to E. Domingo, current Director EEA INTA Bariloche, who allowed us to work in the Pilcaniyeu experimental field. D. Sarasqueta incubated the eggs and J. Von Thüngen collaborated during the fieldwork. Financial support was provided by the Secretaría de Ciencia y Técnica of the Universidad Nacional de Córdoba, and the 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. The study met Argentine legal requirements, and the current Director of the fauna agency of Río Negro province, Mauricio Failla, authorized us to collect the Lesser Rhea orphan eggs.

References

  1. Barri FR, Navarro JL, Martella MB (2008) Effects of hunting, egg harvest and livestock grazing intensities on density and reproductive success of wild Lesser Rheas in Patagonia. Oryx (in press). http://www.epress.ac.uk/oryx/webforms/submission.php?id=2362&article=334
  2. Barri FR, Navarro JL, Martella MB (2006) Breeding success of wild Lesser Rhea (Rhea pennata pennata) populations, at two different livestock densities and biomass production. In: 24th Int Ornithol Congr. J Ornithol 147[Suppl 1]:134Google Scholar
  3. Bellis LM, Navarro JL, Vignolo P, Martella MB (2005) Habitat preferences of Lesser Rhea in Argentine Patagonia. Biodivers Conserv 69:90–93Google Scholar
  4. 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
  5. Giai A (1943) El ñandú overo o “cheuque”, en cautividad. El Hornero 8:471–480Google Scholar
  6. Hanford PT, Mares MA (1985) The mating systems of Ratites and Tinamous: an evolutionary perspective. Biol J Linn Soc 25:77–104CrossRefGoogle Scholar
  7. Lábaque MC, Navarro JL, Martella MB (2004) Effects of storage time on hatchability of artificially incubated greater rhea (Rhea americana) eggs. Br Poult Sci 45:638–642CrossRefPubMedGoogle Scholar
  8. Lábaque MC (2005) Productividad, adaptación y conservación del Ñandú (Rhea americana). PhD thesis. Facultad de Cs. Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, ArgentinaGoogle Scholar
  9. León R, Bran D, Collantes M, Paruelo JM, Soriano A (1998) Grandes unidades de vegetación de la Patagonia. Ecol Austral 8:125–144Google Scholar
  10. Navarro JL, Martella MB, Cabrera MB (1998) Fertility of greater rhea orphan eggs: conservation and management implications. J Field Ornithol 69:117–120Google Scholar
  11. Navarro JL, Martella MB (2002) Reproductivity and raising of greater rhea (Rhea Americana) and Lesser Rhea (Pterocnemia pennata). Archiv Geflügelkunde 66:124–132Google Scholar
  12. Navarro JL, Barri FR, Maestri DM, Labuckas DO, Martella MB (2003) Physical characteristics and chemical composition of Lesser Rhea (Pterocnemia pennata) eggs from farmed populations. Br Poult Sci 44:586–590CrossRefPubMedGoogle Scholar
  13. Novaro AJ, Funes MC, Walker R (2000) Ecological extinction of native prey of carnivore assemblage in Argentine Patagonia. Biol Conserv 92:25–33CrossRefGoogle Scholar
  14. Oring LW (1982) Avian mating systems. In: Farner DS, King JR, Parkes KC (eds) Avian biology, vol 6. Academic Press, New York, pp 1–92Google Scholar
  15. IUCN (2007) 2007 IUCN Red list of threatened species. IUCN. Gland, Switzerland. http://www.redlist.org. Accessed 23 February 2007
  16. Sarasqueta DV (1988) Observaciones sobre la biología del choique o Ñandú petiso (Pterocnemia pennata) de la Patagonia. Presencia 15:17–22Google Scholar

Copyright information

© Dt. Ornithologen-Gesellschaft e.V. 2008

Authors and Affiliations

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

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