Pioneering research on avian behaviour and cognitive neuroscience have highlighted that avian species, mainly corvids and parrots, have a cognitive toolkit comparable to apes and other large-brained mammals, despite conspicuous differences in their neuro-architecture. This cognitive toolkit is driven by convergent evolution, and consists of complex processes such as casual reasoning, behavioural flexibility, imagination and prospection. Here, we review experimental studies in corvids and parrots that tested complex cognitive processes within this toolkit. We then provide experimental examples for the potential involvement of metacognitive skills in the expression of the cognitive toolkit. We further expand the discussion of cognitive and metacognitive abilities in avian species suggesting that an integrated assessment of these processes, together with revised and multiple tasks of mirror self-recognition, might shed light on one of the most highly debated topics in the literature, self-awareness in animals. Comparing the use of multiple assessments of self-awareness within species and across taxa will provide a more informative, richer picture of the level of consciousness in different organisms.