Cross-fostering New Zealand's black stilt

Published source details Reed C.E.M., Nilsson R.J. & Murray D.P. (1993) Cross-fostering New Zealand's black stilt. Journal of Wildlife Management, 57, 608-611.
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This study is summarised as evidence for the following.

	Action	Category
	Foster eggs or chicks of waders with wild non-conspecifics (cross-fostering) Action Link
	Foster eggs or chicks of waders with wild conspecifics Action Link
	Artificially incubate and hand-rear waders in captivity Action Link

Foster eggs or chicks of waders with wild non-conspecifics (cross-fostering)

A replicated and controlled study in mountain streams and rivers in South Island, New Zealand, in the austral springs of 1981-7 (Reed et al. 1993) found that fledging success of managed black stilt Himantopus novasezelandiae nests was at least ten times that reported from unmanaged nests (13-27 chicks fledging in the population each year, a 20-42% fledging rate vs. 2% reported in another study for unmanaged nests). Eggs were removed from black stilt nests and artificially incubated (see ‘Artificially incubate and hand-rear birds in captivity’), before being returned as they were hatching. If replacement in the original nest was not possible then eggs were placed in a foster nest, either another black stilt nest or a black-winged stilt H. himantopus nest. Fledging rates and recruitment to the local population were higher for chicks fostered by black stilts than cross-fostered chicks (66% of 50 chicks fostered by black stilts were resighted and five recruited locally vs. 19% of 21 cross-fostered chicks, with a single recruit). The authors note that cross-fostered chicks followed their foster parents on migration, probably leading to low recruitment.
Foster eggs or chicks of waders with wild conspecifics

A replicated study in South Island, New Zealand (Reed et al. 1993), investigated the survival of black stilts Himantopus novasezelandiae, fostered by both conspecifics and black-winged stilts H. himantopus. This study found that there was higher recruitment into the local population from chicks fostered by conspecifics. The study is discussed in more detail in ‘Foster eggs or chicks with wild non-conspecifics (cross-fostering)’ and ‘Artificially incubate and hand-rear birds in captivity’.
Artificially incubate and hand-rear waders in captivity

A replicated controlled study in South Island, New Zealand (Reed et al. 1993), investigated the survival of black stilts Himantopus novaezelandiae, fostered by both conspecifics and black-winged stilts H. himantopus. The eggs were removed from nests as soon as possible after laying. They were then incubated under a 37.2^oC dry bulb and 28.9^oC wet bulb until 2-3 days before hatching, when the wet bulb was increased to 32.2^oC. Hatching eggs were then returned to the wild. Fledging success of managed nests was at least ten times that reported from unmanaged nests (13-27 chicks fledging in the population each year, a 20-42% fledging rate vs. 2% reported in another study for unmanaged nests).