Problem solving capabilities of Peach-fronted Conures (Eupsittula aurea) studied by the string-pulling test

Many studies have indicated advanced cognitive abilities in different species of parrots and ravens. Here we investigated basic cognitive skills of Peach-fronted Conures (Eupsittula aurea) using the string-pulling test. These small Middle-American parrots are often compared to dolphins due to their similar social structure and great variety of vocalizations, but their problem-solving capabilities have not been studied before. Two to four strings were suspended in different configurations to the underside of a perch. A food reward was attached at the end of one of the strings. The food could not be obtained by flying or reached from the ground. By varying different spatial configurations of strings and rewards, different cognitive skills could be investigated. Four conures (two females and two males) were tested. All four individuals solved three out of four tested string configurations (four straight strings, two slant strings, two contact-no contact strings) within 14 seconds on average, but all failed in a crossed two-string test. Subsequently we tested the birds with a vertical pulley that required the birds to pull the string down to get the food reward within reach from below. In this test males performed significantly better than females. The test showed that Peach-fronted Conures can generalize information from previous experiments and transfer skills to novel situations. Apart from sex differences, there were also differences in the performance of different individuals of the same sex for all experiments. These results suggest that Peach-fronted Conures are able to plan future actions and that they have so-called ‘means-end’ understanding and ‘contact’ und