Abstract:

Corvids, readily adaptable to changes in social and ecological contexts, successfully inhabit almost the entire world. They are perceived as highly intelligent birds and much focus is aimed at their cognitive capabilities. Intriguingly, they are also songbirds with a complete ‘song system’ and demonstrate great vocal control. Thus, corvids offer fantastic opportunities to bridge the fields of cognition and birdsong to study the cognitive building blocks for communication. Inspired by how human speech involves the volitional control of hierarchical, structured vocalizations, my current work examines two critical building blocks: the ability to volitionally control vocal production and the processing of complex sequence structures. Combining numerical abilities and vocal control, we demonstrate that crows can ‘count out loud’, flexibly controlling production of variable numbers of vocalizations to arbitrary, neutral cues. Analyses of the first vocalization of a sequence were predictive of the total number of vocalizations, indicating a planning process. Another project, also focused on sequences, examined if crows could parse complex structures, specifically center-embedded recursive ones. We presented sequences of bracket pair stimuli (e.g. [] and {}) to crows who were instructed to peck at training lists. They were then tested on their ability to transfer center-embedded structures to never-before-seen bracket pairings, revealing recursive capacities. Together, these studies may help uncover the general principles and evolutionary constraints underlying the emergence of voluble, clever animals and their brains.