Action: Artificially incubate and hand-rear vultures in captivity
A study in Peru found that hand-reared Andean condors Vultur gryphus had similar survival to parent-reared birds after release into the wild.
Artificial incubation involves removing eggs from incubating parents and using an incubator to hatch them. Techniques can be extremely complex, with precision humidity and temperature control and turning of the eggs to ensure correct development Hand-rearing can be used with chicks from artificially-incubated eggs or with chicks removed from parents after hatching and involves manually feeding chicks until independence. Both techniques can be used to encourage parents to produce more offspring, or when naturally-raised chicks and eggs have low survival.
Supporting evidence from individual studies
A study using Andean condors Vultur gryphus in arid mountains in Peru in 1980-1 to develop release techniques for Californian condors Gymnogyps californianus (Wallace & Temple 1987) found that there was no difference in survival between hand-reared birds released at natural fledging age (approximately six months old) and parent-reared birds released at between one and three years old (three of five hand-reared birds alive 18 months after release vs. four of six parent-reared birds). All mortalities occurred in the first six months after release. Hand-reared birds were fed using puppets heads (to avoid imprinting on human carers, see ‘Use puppets to increase the survival or growth of hand-reared chicks’ for studies on this intervention). Puppet-reared birds were kept in aviaries at the release site for five months before release, parent-reared birds were kept for seven weeks. After release, parent-reared birds integrated into wild populations faster than puppet-reared birds, and their foraging area increased to approximately 1,300 km2 after 170 days, puppet-reared birds took approximately 320 days to increase foraging area to this size. The authors suggest that they were able to manipulate the foraging behaviour (discussed in ‘Provide supplementary food after release’) of puppet-reared birds more effectively than parent-reared birds. This study is also discussed in ‘Release captive-bred individuals’.