Individual study: Reintroduction of hand-reared scarlet macaws Ara macao to Curú and Golfito, Costa Rica
Brightsmith D. (2004) The use of hand-raised psittacines for reintroduction: a case study of scarlet macaws (Ara macao) in Peru and Costa Rica. Biological Conservation, 121, 465-472
Scarlet macaws Ara macao were formerly widely distributed throughout forests of tropical Central and South America. Hunting, habitat loss and collection for the pet trade have caused numbers to decline and bought about local extinction in many parts of their range. A hand-rearing and reintroduction programme was initiated in Costa Rica at two sites where scarlet macaws had last been seen in the 1950s and 1960s, with the aim of establishing new populations.
Re-introduction sites: Two forested sites in Costa Rica (Curú and Golfito) were slected for reintroductions (Table 1, attached, for summary of release site characteristics). Wild scarlet macaws had last been seen at Curú in the 1960s and at Golfito in the 1950s.
Numbers released and rearing method: At Golfito 38 macaws were released; 22 were hand-reared and seven were raised by their parents at Alajuela Costa Rica Zoo Ave (Golfito), five were ex-pets (removed from the wild as chicks). All 13 birds released at Curú were hand-reared at Amigos de las Aves (Curú).
Human habituation: The young macaws raised at Golfito were separated from most human contact whilst at Curú they were not.
Disease screening: Pre-release disease screenings were carried on all birds.
Releases: Releases took place in January 1999 at Curú, and from May 1999 to December 2001 at Golfito. The rearing and release methods are summarised in Table 2, attached.
Post-release monitoring: At Curú released birds were counted on a daily basis at feeding stations but they were not individually identifiable. Birds released at Golfito on the otherhand, were marked using a combination of black ink marks on the bill, small cuts in the feathers and had radio-collars. This population was counted daily at feeding stations and opportunistically at nest box sites. Daily monitoring of the radio-collared birds was carried out for the first two weeks post-release, once a week during the subsequent three months and irregularly thereafter.
Supplementary feeding and establishment: Social interactions are important in the release of macaws. The provision of supplementary feeding areas which drew birds together, appreared to promote the process of the establishment of core flocks. Feeding also facilitated monitoring and helped newly released birds to locate the established flock. The slow establishment of a core flock is thought to be one reasons for the lower survival seen at Golfito (Table 3, attached). Supplementary feeding continued throughout the study period but within a year of release, most birds were feeding almost entirely on wild food.
Disease screening: No diseases were found in birds prior to release.
Survival: Birds at Curú and Golfito adapted well to life in the wild, forming coherent flocks, stable pairs and a few attempting to breed (Table 3).
Some of the released birds showed little fear of humans. The five ex-pets socialised less with the other released macaws, remained close to the release area, perched lower in trees and overall were found to be the worst release candidates. In spite of this, all five survived at least two years post-release.
The absence of, or presence of only low densities of avian predators large enough to take the macaws i.e. Spizatus hawk eagles, probably increased release success. No hawk eagles were present at Curú and only low densities were present at Golfito. It is assumed that hand-reared released birds with no experience of wild predators or predator avoidance would be exceptionally vulnerable to such predators.
Conclusions: These releases indicate that hand-reared scarlet macaws can establish in the wild but long-term viability will be dependant upon successful breeding. Breeding attempts to date suggests that breeding is likely to take place in the near future. Higher reproductive success is expected amongst the parent raised birds, if this is the case this will be taken into account in future release programmes.
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