Ontogeny of tool use in New Caledonian crows

Speaker:
Christian Rutz

Authors:
Christian Rutz, Ben Kenward, Alex Weir, Alex Kacelnik

Abstract:

While Alex Weir focuses in his talk on the tool-oriented behaviour of adult New Caledonian crows, I shall investigate in my presentation how these skills develop in juvenile birds. To examine the interaction between inherited traits, individual learning and social transmission, we observed the ontogeny of twig tool use in four captive-bred, hand-reared crows. Two of the juveniles received daily demonstrations of tool use, in which a human foster parent extracted food from holes and crevices. The other two juveniles never saw tool use, but otherwise received the same degree of overall contact with their human caretakers. All four juveniles developed functional twig tool use, with no obvious difference in the onset of tool using between treatment groups. Interestingly, successful food retrieval was preceded by stereotyped object manipulation action patterns that resembled components of the mature behaviour, demonstrating that tool-oriented behaviours in this species are an evolved specialization. However, tutored juveniles showed higher levels of handling and insertion of twigs than did their naive counterparts, and a simple choice experiment showed that they preferred to handle objects that they had seen being manipulated by their human foster parent. Our observations reveal that individual learning, cultural transmission and creative problem solving all contribute to the acquisition of tool-oriented behaviours in this species. I hope these findings may be of interest to AI experts, as they illustrate how a rich interplay of different mechanisms results in sophisticated, flexible behaviour.

References:

Kenward, B., Rutz, C., Weir, A.A.S., & Kacelnik, A. (2006). Development of tool use in New Caledonian crows: inherited action patterns and social influence. Animal Behaviour 72: 1329-1343.

Kenward, B., Weir, A.A.S., Rutz, C., & Kacelnik, A. (2005). Tool manufacture by naive juvenile crows. Nature 433: 121.