Action Synopsis: Bird Conservation About Actions

Foster eggs or chicks of parrots with wild conspecifics

How is the evidence assessed?
  • Effectiveness
  • Certainty
  • Harms

Key messages

  • A replicated study from Venezuela found that yellow-shouldered Amazon Amazona barbadensis chicks had high fledging rates when fostered to conspecific nests in the wild.
  • A second replicated study from Venezuela found significantly lower poaching rates of yellow-shouldered Amazons Amazona barbadensis when chicks were moved to foster nests closer to a field base.


About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. A 1998 review of a yellow-shouldered Amazon Amazona barbadensis release programme on Margarita Island, Venezuela (Sanz & Grajal 1998), found that, of 53 nestlings fostered to wild nests between 1989 and 1996, 44 (83%) chicks eventually fledged. The population on the island increased from 750 to approximately 1900 individuals between 1989 and 1996 as a result of recruitment increasing from zero in 1989 to 53 birds/year following management. This study is discussed in more detail in ‘Release captive-bred individuals’, ‘Artificially incubate or hand-rear birds in captivity’ and ‘Use education programmes and local engagement to help reduce pressures on species’.

    Study and other actions tested
  2. A replicated study in 2005-2006 (part of a longer study from 2000-2009) in 18 monitored yellow-shouldered Amazons Amazona barbadensis nests in tropical forest habitat on Margarita Island, Venezuela (Briceño-Linares et al. 2011) found that fostering fledglings and assisted breeding significantly decreased poaching rates.  The use of foster nests and assisted breeding in 2005 decreased poaching from 56% at the end of 2004 to 18% in 2005 and 0% poaching in of monitored nests in 2006. Fledglings from high-risk nests (further away from the base) in the study area were moved to foster nests (possessing similarly aged fledglings) near the field base. All fledglings from each nest were then removed and placed them in a labelled wooden box in a secure facility after sunset, and returned to the nest at sunrise. This strategy was initiated once the parents stopped spending the night inside the nests, around 30–40 days after hatching. This study is also discussed in ‘Relocate nestlings to reduce poaching’, ‘Use education programmes and local engagement to help reduce pressures on species’, ‘Employ locals as biomonitors’ and ‘Foster eggs or chicks with wild conspecifics’.

    Study and other actions tested
Please cite as:

Williams, D.R., Child, M.F., Dicks, L.V., Ockendon, N., Pople, R.G., Showler, D.A., Walsh, J.C., zu Ermgassen, E.K.H.J. & Sutherland, W.J. (2020) Bird Conservation. Pages 137-281 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.


Where has this evidence come from?

List of journals searched by synopsis

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Bird Conservation

This Action forms part of the Action Synopsis:

Bird Conservation
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What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

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