Tool making cockatoos adjust the lengths but not the widths of their tools to function Auersperg, A. M. I. ; Köck, C. ; O'Hara, M. ; Huber, L. Abstract Publication: PLoS ONE Pub Date: November 2018 DOI: 10.1371/journal.pone.0205429 Bibcode: 2018PLoSO..1305429A