Abstract
Previous research on African grey parrots (Psittacus erithacus) has confirmed their ability to sort photographs based on the identity of the conspecific pictured, therefore indicating presence of individual recognition (IR) in this species. The aim of the research presented was to shed light upon some aspects of African greys' appearance and their significance in IR.
In order to explore visual IR in African greys, three subjects (1 female, 2 males) were tested using matching-to-sample cognitive tasks. Modified as well as non-modified photographs of familiar conspecifics were used as sample stimuli to allow comparison of subjects' success rate in modified vs. non-modified trials.
Overall, 16 different modifications were created. Visual aspects we focused on were the following: coloration and structure of plumage, body shape, level of detail, particular body parts and their configuration; as well as those found significant in humans when it comes to IR based on faces - such as the negative effect of spatial inversion and color inversion.
Modifications that targeted structure and coloration of plumage had the most prominent impact (in contrast to success rate in non-modified trials), followed by those that obscured conspecifics' shape or abdomen. On the other hand, success rate in trials containing modifications that related to head and facial features was comparable to non-modified trials, suggesting that these features do not play a major role in a successful recognition.