The Influence of the Breeding Method on the Behaviour of Adult African Grey Parrots (Psittacus Erithacus)

Abstract

1. Introduction

African grey parrots (Psittacus erithacus) are very commonly kept as companion animals all over the world. Hand-rearing has been increasingly carried out over the last 25 years. Nowadays, thanks to innovative ready-to-use feeding formulas, previous experience in that celd gathered by numerous breeders and high technology equipment (Veren and Jordan, 1992; Wagner, 1999; Reinschmidt, 2000; Low, 1987) hand-rearing is much easier to accomplish. However, the exact consequences of the different hand-rearing methods have never been studied and still remain unknown. It is still not clear how long the sensitive stage, during which the birds are imprinted on one spectre species, lasts. Still, the development of the chicks' normal behaviour seems to go beyond their nesting period and to involve many components that have to be learned by interaction with parrots and observation of other individuals in the rock. For instance, the importance of the sibling relationship was demonstrated by Wanker (1996) in the case of spectacled parrotlets.

To the authors' knowledge, the few previous studies about hand-rearing in parrots all consider the effects of hand-rearing on the birds' sexual and social behaviour with conspeci res. Sistermann (2000) demonstrated that hand-rearedmacaws, African grey parrots and cockatoos have signiccantly more problems breeding and bonding with conspeci res than birds that have not been hand-reared. Further study showed that handrearing had differential effects on the sexual behaviour of male and female cockatiels (Myers et al., 1988) and impaired the ability of isolated lovebirds to socialize with conspeci res (Preiss and Franck, 1974).

Hand-reared parrots choose a speci cc human being as a partner. This triggers frustration to the birds, as their human bonds cannot fully satisfy their social requirements and often do not understand or do not react compatibly to the birds' body language. Thus, hand-reared grey parrots may develop frustration-related or attentionseeking behavioural disorders, like aggressiveness, feather picking, stereotypies or abnormal sexual behaviours. Contrary to parent-reared parrots, which often also bond to one person, hand-reared parrots are imprinted on humans and seem to be socially more dependent on them. Therefore, we expect them to be prone to develop such frustration-related disorders.

 There are many alternatives to hand-rearing. Under certain circumstances, foster parents can be used to rear chicks. Further, if the parents do not feed their offspring suttcientlv, supplementary feeds can be given. This method usually has the added advantage of producing chicks which are tame. Finally, neonatal handling is a method which allows the breeders to supply tame birds. Handled orange-winged Amazon chicks were proved to be tamer by all measures of tameness than the birds belonging to the control group (Colette et al., 2000). The predisposition of Dial imprinting to occur at one particular developmental stage could not be stated (Aengus and Millam, 1999). But even if this were the case, Aengus and Millam doubt this sensitive phase exists before approximately the 14th day of life because eyes and ears are not open until then.

Although grey parrots' adaptation ability is rather good, it is limited in terms of time and they often develop behavioural problems in captivity. The trauma endured by African grey parrots that were captured in the wild must be considerable and may have long-lasting consequences on the behaviour of the birds, like the development of phobic behaviours. In spite of the impressive intelligence of African grey parrots, which has been estimated to be comparable to that of a 5-year-old child, most parrots possess the emotional development of a 28!-year-old child (Pepperberg, cited by Davis, 1991).