Relationship Quality and Cognition in Orange-Winged Amazons (Amazona amazonica) and Blue and Gold Macaws (Ara ararauna)

Evidence of cognitive complexity in birds has led to the recognition that mammalian and avian species likely evolved comparable high-level cognitive capacities independently. One of the most significant findings that have emerged from this area of study is the identification of a key social trait that is found in species deemed to be intelligent – the presence of long-term, high-quality partnerships. Amongst birds, parrots (along with corvids) have shown relatively high levels of both cognitive and social complexity. However, relatively few parrot species have been the subject of empirical investigation. The original research presented in this thesis explores social behaviour and cognitive capacity in orange-winged Amazons (Amazona amazonica) and blue and gold macaws (Ara ararauna). Observational research findings revealed evidence of high-quality relationships in both species, and while levels of affiliative investment were similar in orange-winged Amazons (OWAs) and blue and gold macaws (BGMs), some potentially meaningful between species differences were found in courtship feeding, allopreening, and social tolerance. Experimental research findings revealed evidence of inhibitory control in both species (as measured by performance on a transparent cylinder task), though OWAs performed significantly better than BGMs on test trials. Social learning capacities were also found in OWAs through an open diffusion experiment. Both species showed poor performance in a means-end task, yielding no evidence of causal understanding. Birds also had difficulty acquiring the loose string task, which was aimed at testing cooperative problem solving. Poor performance of both OWAs and BGMs on these tasks is believed to have been primarily due to non-cognitive factors (e.g., motivation, motor difficulty of task). Affiliative investment and performance on the social learning task were found to be positively correlated in BGMs and there was some indication that individual variation in boldness may have been associated with inhibitory task performance in BGMs.