Movements of translocated captive-bred and released Critically Endangered kaki (black stilts) Himantopus novaezelandiae and the value of long-term post-release monitoring

Published source details van Heezik Y., Maloney R.F. & Seddon P.J. (2009) Movements of translocated captive-bred and released Critically Endangered kaki (black stilts) Himantopus novaezelandiae and the value of long-term post-release monitoring. Oryx, 43, 639-647.
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This study is summarised as evidence for the following.

	Action	Category
	Release birds in groups Action Link
	Release captive-bred individuals into the wild to restore or augment wild populations of waders Action Link
	Release birds as adults or sub-adults, not juveniles Action Link

Release birds in groups

A replicated study of critically endangered black stilt (kaki) Himantopus novaezelandiae releases in South Island, New Zealand, between 1993 and 2005 (van Heezik et al. 2009) found that birds were more likely to move long distances from the release site when released in large groups, compared to birds released in smaller numbers. This study is discussed in more detail in ‘Release captive-bred individuals’ and ‘Release birds as adults or sub-adults, not juveniles’.
Release captive-bred individuals into the wild to restore or augment wild populations of waders

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’.
Release birds as adults or sub-adults, not juveniles

A review of black stilt (kaki) Himantopus novaezelandiae releases in South Island, New Zealand, between 1993 and 2005 (van Heezik et al. 2009) found that 20% of 150 birds released as juveniles (60-90 days old) and 13% of those released as sub-adults (nine months old) were alive two years after release (with 25 juvenile releases and 52 sub-adults not yet at breeding age). Neither group was more likely to be seen at the release site. Eggs came from both wild and captive birds and were artificially-incubated until hatching. This study is discussed in more detail in ‘Release captive-bred individuals’ and ‘Release birds in groups’.