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


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.


Conservation Eggs Management Lesser Rhea Reproduction 



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.


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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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