Foster eggs or chicks of bustards with wild conspecifics
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
Background information and definitions
Natural variations in reproductive output can be detrimental when populations are very small, for example if pairs fail to produce fertile eggs or some pairs repeatedly fail to raise offspring successfully. One way to minimise this problem is to foster eggs and chicks between nests. Eggs and chicks from nests with more offspring than they are likely to be able to raise can be moved to those with infertile eggs. Alternatively, if a pair produces fertile eggs or healthy chicks but consistently fails to raise chicks then it may be possible to transfer offspring to a more successful pair.
In other circumstances it may be possible to foster chicks with other species (‘cross-fostering’). Studies describing this intervention are discussed in the following section ‘Foster eggs or chicks with wild non-conspecifics (cross-fostering).’
Supporting evidence from individual studies
A small trial in a desert site in desert steppe in southwest Saudi Arabia in 1995 (Gelinaud et al. 1997) found that a released, captive-bred female houbara bustard Chalmydotis undulata macqueenii successfully raised a captive-laid egg fostered into her nest. The chick hatched and fledged at 41 days old. The female had originally laid a single, infertile egg. The release programme is discussed in ‘Release captive-bred individuals’.Study and other actions tested