Tool use and manufacture in the Goffin’s cockatoo (Cacatua goffini) (#242)
Innovative tool use and manufacture in species not adaptively specialized for doing so may represent an significant step in understanding the evolution of advanced cognitive processing in the technical domain. Following an accidental aviary observation, we showed how a captive male Goffin’s cockatoo successfully and reliably broke stick-type tools out of larch wood and used them to rake food into his reach. Thereby he developed a sophisticated technique, adjusting the functional end of his tool to the changing position of the food reward and overcame various morphological (eg. beak curvature) and ecological constraints (eg. not a habitual tool user; not a nest builder). To investigate whether similar behaviours could be transmitted to other individuals we used the respective innovator as a demonstrator. Subjects observing tool-using demonstrations showed greater overall interaction with the relevant parts of the apparatus than subjects observing magnetic ‘ghost’ controls. Notably, all three males in the demonstration group acquired tool-using skills. Two of these birds further accomplished larch-tool-making competence, one without requiring further demonstrations. To see whether the stick-like shape of the manufactured tools was acquired accidentally (eg. by breaking it along the growth lines of the wood) all tool-using subjects were later confronted with three additional types of material (cardboard, leafed beech twigs and bee wax-combs). Further functional tools out of cardboard and beech twigs were successfully and reliably built and used