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Providing evidence to improve practice

Action: Release captive-bred individuals into the wild to restore or augment wild populations of waders Bird Conservation

Key messages

Read our guidance on Key messages before continuing

A review of black stilt Himantopus novaezelandiae releases in New Zealand found that birds had low survival (13–20%) and many moved away from their release sites so, in consequence, that they could not be managed and were unlikely to interact with stilt populations in the wild.


Supporting evidence from individual studies


A review of critically endangered black stilt (kaki) Himantopus novaezelandiae releases in riverine habitats in South Island, New Zealand, between 1993 and 2005 (van Heezik et al. 2009) found that 13-20% of 464 birds released were alive two years after release. However, 32% of birds that reached breeding age did not remain at their release site and 15% moved to an area where they could no longer be managed and were unlikely to reproduce successfully. The authors argue that this second category of birds is “effectively dead” as they no longer contribute to the wild population. Birds were released into populations that needed supplementation; therefore movements away from the release site could also be detrimental. Eggs were taken from wild and captive-bred birds and artificially incubated. Birds were not held at the release site before release, but food was provided at release site for between six weeks and two months. This study is also discussed in ‘Release birds as adults or sub-adults, not juveniles’ and ‘Release birds in groups’.


Referenced papers

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. (2019) Bird Conservation. Pages 141-290 in: W.J. Sutherland, L.V. Dicks, N. Ockendon, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2019. Open Book Publishers, Cambridge, UK.