The hornbill and the pitcher: a southern ground hornbill (Bucorvus leadbeateri) learns to solve the Aesop’s Fable task

Abstract

Applying widely used tasks to test the problem solving of species with distinct ecological and social structures facilitates a comprehensive understanding of selective pressures for cognitive traits, such as insight, innovation, and causal reasoning. A southern ground hornbill (Bucorvus leadbeateri) was presented with a version of the Aesop’s Fable task to extend explorations of problem solving in this paradigm to a species that has heretofore been understudied. After learning to perform the task, our subject was presented with a version in which heavy stones were more efficient than light stones in displacing a water column to bring food rewards within reach. Although she successfully retrieved rewards more quickly across sessions and learned to select, lift, and drop stones into the tube, she did not preferentially select heavy stones to complete the task, performing similarly to previously tested species. Despite the single subject not demonstrating any causal understanding of the property of weight in this task, the results demonstrate that hornbills will engage with novel object manipulation tasks and do not preclude the possibility that hornbills could evidence such understanding. Gaining a better understanding of the cognitive abilities of southern ground hornbills may ultimately contribute to improving husbandry and conservation efforts in this vulnerable species.