No evidence of mirror self-recognition in keas and Goffin’s cockatoos

So far only one bird species, a corvid, passed the mark test for mirror self-recognition (MSR) although the results have been questioned. We examined the capacity for MSR in another large-brained avian taxon, parrots, with keas (Nestor notabilis) and Goffin's cockatoos (Cacatua goffini). After several weeks of mirror habituation, they were subjected to the mark test using different marks and mark placements while facing horizontal and vertical mirrors simultaneously. The keas had an additional control condition in which their reaction towards a marked or non-marked con-specific behind a transparent partition was compared to their own reflection. No evidence of MSR was found in either species. Keas responded to their reflection comparably to a con-specific behind a clear separation. Goffin's cockatoos showed fewer social responses towards their horizontal reflection compared to their vertical reflection, suggesting that they may interpret them differently.