Lateral asymmetry in the freely occurring behaviour of budgerigars (Melopsittacus undulatus) and its relation to cognitive performance

Hemispheric laterality and its provision of potential fitness advantages to aves is a widespread topic of research in budgerigars and other parrot species [e.g., Magat, M. & Brown, C. (2009). Laterality enhances cognition in Australian parrots. Proceedings of the Royal Society B: Biological Sciences, 276, 4155-4162]. In the current study, lateral preferences were tracked for 11 captive-reared budgerigars that subsequently underwent 2 cognitive problem-solving tests: a tool-use problem and a dig-discrimination task. Two significant individual-level lateral preferences (a leftward unipedal support preference and a rightward preening side preference) and 1 significant population-level preference (a right-side preening preference) were obtained. Lateral preening side preference indices for individual subjects correlated with various measures of performance on the dig task, such that right-side preening preferences and stronger lateral preferences irrespective of direction were associated with enhanced dig task performance. The data generally support the idea that laterality in aves serves as a good predictor of increased cognitive capability, while also offering new evidence for population-level lateral preferences in the species.