Very few animals are able to reproduce and learn orally the sounds heard, among human mammals, elephants, cetaceans, seals and bats, and among birds, singing birds, parrots and hummingbirds. Although to do so it was considered that great cognitive abilities are needed, until now there has been no clear evidence of the relationship between both characteristics.

This study analyzed the songbirds, namely 214 birds of 23 different species. They have measured the verbal complexity of these species, taking into account the number of songs and calls in their repertoire, their ability to learn new songs and their ability to mimic other species. And with these birds, they've done experiments to measure their cognitive abilities, like problem solving, association and self-control.

Statistical studies show the strong correlation between problem-solving capacity and oral learning capacity. Among the birds studied, the Arabs (Sturnus vulgaris), the blue corners (Cyanocitta cristata) and the gray languages (Dumetella carolinensis) were the most competent in the study of sounds, as well as in problem solving and overcoming obstacles. In addition, researchers have observed that more competent species have higher brains than body size.