Why is reintroduction of northern bald ibis Geronticus eremita so complicated? An overview of recent progress and potential

Published source details Bowden C.G.R., Boehm C., Jordan M.J.R. & Smith K.W. (2007) Why is reintroduction of northern bald ibis Geronticus eremita so complicated? An overview of recent progress and potential. Pages 27-35 in: Toronto, Onatario, Canada.
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This study is summarised as evidence for the following.

	Action	Category
	Use microlites to help birds migrate Action Link
	Foster eggs or chicks of ibises with wild non-conspecifics (cross-fostering) Action Link
	Artificially incubate and hand-rear storks and ibises in captivity Action Link
	Release captive-bred individuals into the wild to restore or augment wild populations of storks and ibises Action Link
	Clip birds’ wings on release Action Link
	Use captive breeding to increase or maintain populations of storks and ibises Action Link
	Use holding pens at release sites Action Link
	Release birds as adults or sub-adults, not juveniles Action Link

Use microlites to help birds migrate

A 2007 review of northern bald ibis (waldrapp) Geronticus eremita conservation (Bowden et al. 2007) found that a group of ibis successfully followed a microlite from Austria to Italy in 2004. However, by 2006, no birds had successfully returned, although several had made northwards journeys of up to 300 km. This study also discusses several other ex situ conservation interventions, discussed in the relevant sections.
Foster eggs or chicks of ibises with wild non-conspecifics (cross-fostering)

A 2007 review of northern bald ibis (waldrapp) Geronticus eremite conservation (Bowden et al. 2007) found that raising ibis chicks with cattle egrets Bubulcus ibis was not successful. This study discusses several ex situ interventions, described in the relevant sections.
Artificially incubate and hand-rear storks and ibises in captivity

A 2007 review of northern bald ibis (waldrapp) Geronticus eremita conservation (Bowden et al. 2007) found that intensive hand-rearing of ibis chicks by a small number of human foster-parents appeared to lead to the formation of strong bonds between chicks which appear important in successful releases of the species. This study is also discussed in ‘Use captive breeding to increase or maintain populations’, ‘Release captive-bred individuals into the wild to restore or augment wild populations’, ‘Use holding pens at release sites’, ‘Release birds as adults or sub-adults, not juveniles’, ‘Clip birds’ wings on release’, ‘Use microlites to help birds migrate’ and ‘Foster birds with non-conspecifics’.
Release captive-bred individuals into the wild to restore or augment wild populations of storks and ibises

A 2007 review of northern bald ibis (waldrapp) Geronticus eremita conservation (Bowden et al. 2007) found varying success in release programmes, dependent on the techniques used. Trials in Israel using a variety of techniques (described in ‘Release birds as adults or sub-adults, not juveniles’ and ‘Clip birds’ wings on release’) found that all 56 birds released became emaciated and disorientated and formed poor social bonds. Similarly, the release of 73 birds in Spain between 2004 and 2006 has not resulted in the formation of a stable colony. However, the release of 43 birds in Austria has led to the establishment of a colony in the wild. This study is also discussed in ‘Use captive breeding to increase or maintain populations’, ‘Artificially incubate and hand-rear birds in captivity’, ‘Use holding pens at release sites’, ‘Release birds as adults or sub-adults, not juveniles’, ‘Clip birds’ wings on release’, ‘Use microlites to help birds migrate’ and ‘Foster birds with non-conspecifics’.
Clip birds’ wings on release

A 2007 review of northern bald ibis (waldrapp) Geronticus eremita conservation in Israel (Bowden et al. 2007) found no differences in survival between 16 birds released with clipped wings and 40 birds released without clipping. All 56 birds released became emaciated and disorientated and formed poor social bonds. This study is also discussed in ‘Release captive-bred individuals into the wild to restore or augment wild populations’, ‘Use captive breeding to increase or maintain populations’, ‘Artificially incubate and hand-rear birds in captivity’, ‘Use holding pens at release sites, ‘Release birds as adults or sub-adults, not juveniles’, ‘Use microlites to help birds migrate’ and ‘Foster birds with non-conspecifics’.
Use captive breeding to increase or maintain populations of storks and ibises

A 2007 review of northern bald ibis (waldrapp), Geronticus eremita, conservation (Bowden et al. 2007) found that three lineages of birds in North America, Japan and Europe, comprising a total of 1,150 birds were produced from an original 150 birds taken from the wild in Morocco in 1988. About 800 additional birds are also thought to be present in captivity but are not registered. However, a programme at a group of zoos, headed by Munich Zoo, failed to establish a productive captive colony for three years. The authors note that ibises frequently swallow small objects they find including nails and wire, which has led to many birds dying from a punctured gut. This study is also discussed in ‘Release captive-bred individuals into the wild to restore or augment wild populations’, ‘Artificially incubate and hand-rear birds in captivity’, ‘Use holding pens at release sites’, ‘Release birds as adults or sub-adults, not juveniles’, ‘Clip birds’ wings on release’, ‘Use microlites to help birds migrate’ and ‘Foster birds with non-conspecifics’.
Use holding pens at release sites

A 2007 review of northern bald ibis (waldrapp) Geronticus eremita conservation (Bowden et al. 2007) found that the seasonal use of holding pens, designed to prevent birds from migrating from a release site in Turkey, kept the majority of released individuals in the area, but over 25 years some 200 birds avoided capture and were ‘lost’ from the colony. Previous work had found that migrating birds were unlikely to survive or return. These birds migrated but never returned the following spring. This study is also discussed in ‘Release captive-bred individuals into the wild to restore or augment wild populations’, ‘Use captive breeding to increase or maintain populations’, ‘Artificially incubate and hand-rear birds in captivity’, ‘Release birds as adults or sub-adults, not juveniles’, ‘Clip birds’ wings on release’, ‘Use microlites to help birds migrate’ and ‘Foster birds with non-conspecifics’.
Release birds as adults or sub-adults, not juveniles

A 2007 review of northern bald ibis (waldrapp) Geronticus eremite conservation (Bowden et al. 2007) found no differences in survival between birds released in Israel as breeding adults, juveniles or fledglings. All 56 birds released became emaciated and disorientated and formed poor social bonds. This study is also discussed in ‘Release captive-bred individuals into the wild to restore or augment wild populations’, ‘Use captive breeding to increase or maintain populations’, ‘Artificially incubate and hand-rear birds in captivity’, ‘Use holding pens at release sites, ‘Clip birds’ wings on release’, ‘Use microlites to help birds migrate’ and ‘Foster birds with non-conspecifics’.