Cerebral lateralization determines hand preferences in Australian parrots.

Individual preference for the use of one limb over the other to explore the environment or manipulate objects is common trait among vertebrates. Here, we explore the hypothesis that limb preference is determined by the engagement of a particular cerebral hemisphere to analyse certain stimuli. We recorded the eye and foot preferences of 322 individuals from 16 species of Australian parrots while investigating potential food items. Across all species, eye preferences explained 99 per cent of the variation in foot use in Australian parrots. The vast majority of species showed significant relationships between eye and foot preferences at the population level.