Action: Artificially incubate and hand-rear parrots in captivity
- Two studies from South America describe the successful hand-rearing of parrot chicks, with ten of 12 yellow-shouldered amazons Amazona barbadensis surviving for a year after release and blue-fronted amazons Amazona aestiva fledging at higher weights than wild birds.
- A review of the kakapo Strigops habroptilus management programme found that chicks could be successfully raised and released, but that eggs incubated from a young age had low success.
- A study from the USA found that all hand-reared thick-billed parrots Rhynchopsitta pachyrhyncha died within a month of release: significantly lower survival than for wild-caught birds also translocated to the release site.
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 in southeast Arizona, USA (Snyder et al. 1994), released seven hand-reared thick-billed parrots Rhynchopsitta pachyrhyncha into the Chiricahua Mountains between September 1986 and September 1993 as part of a wider release and translocation programme. None was alive a month after release. This was significantly lower survival than wild-caught birds translocated as part of the same programme. This study is discussed in more detail in ‘Release captive-bred individuals’, ‘Translocate Individuals’ and ‘Use holding pens at release sites’.
A small study in 1990-1 on Margarita Island, Venezuela (Sanz & Grajal 1998), found that all 14 yellow-shouldered amazon Amazona barbadensis chicks hand-reared at a release centre fledged successfully. Two of the birds were killed by predators before release, but the remaining 12 were released and at least ten survived for at least a year (see ‘Release captive-bred individuals’ for details). Hand-rearing involved feeding birds three times a day using a syringe with commercial parrot food and fruits. From 55 days old, chicks were provided with chunks of fruit and whole fruits. This study is also discussed in ‘Foster eggs or chicks with wild conspecifics’ and ‘Use education programmes and local engagement to help reduce pressures on species’.
A 2001 review of data from the kakapo Strigops habroptilus management programme in New Zealand (Elliott et al. 2001) found that 22 chicks were removed from nests between 1992 and 1999, with nine surviving (41%) and being released into the wild. These nine represent 60% of the 15 birds fledged between 1990 and 2001. However, the authors note that eggs artificially incubated from an age of less than ten days old had low success rates. None of the birds raised had reached breeding age by the time of the review, so their breeding behaviour and success was unknown.
A replicated, controlled study at a rehabilitation centre in southern Brazil in 1997-9 (Seixas & Mourao 2003) found that hand-reared blue-fronted amazons Amazona aestiva grew for longer than wild birds (with an average growth period of 64 days for 124 captive-reared birds vs. 56 days for 86 wild nestlings). This meant that fledging weights of captive-reared birds were significantly higher than wild birds (average weights of 401.g for 34 captive males and 362 g to 28 females vs. 364 g for nine wild males and 343 g for 12 wild females). Birds were initially fed on a mix of mashed fruit, vegetables, corn flour and puppy food three times per day, changing to fruit, vegetables, seeds and grain as they grew.
- Snyder N.F.R., Koenig S.E., Koschmann J., Snyder H.A. & Johnson T.B. (1994) Thick-billed parrot releases in Arizona. The Condor, 96, 845-862
- Sanz V. & Grajal A. (1998) Successful reintroduction of captive-raised yellow-shouldered Amazon parrots on Margarita Island, Venezuela. Conservation Biology, 12, 430-441
- Elliott G.P., Merton D.V. & Jansen W.P. (2001) Intensive management of a critically endangered species: the kakapo. Biological Conservation, 99, 121-133
- Seixas G.H.F. & Mourão G. (2003) Growth of nestlings of the blue-fronted amazon (Amazona aestiva) raised in the wild or in captivity. Ornitologia Neotropical, 14, 295-305