Birds have more concentrated brainpower than mammals

Parrots and corvids have just as many nerve cells in their forebrains as mammals — in a much smaller space.

Editorial team Wild beim Wild — 16 June 2016

Although the brains of parrots and crows are walnut-sized, these birds display remarkable intelligence.

This comes as no surprise, since their brains are packed with far more nerve cells than those of mammals.

The cognitive abilities of birds have repeatedly astonished researchers: ravens and jays are aware when they are being watched and only hide their food when unobserved, magpies recognise themselves in mirrors, and crows craft sophisticated tools.

Parrots can learn and meaningfully use hundreds of words, spontaneously dance to a rhythm, and use sticks to drum on trees. How they manage all of this with their “bird brains” has until now been a mystery.

Led by Pavel Nemec of Charles University Prague, researchers have now counted the brain nerve cells of 28 bird species and discovered that birds possess just as many in their forebrains as mammals do in their much larger skulls. The forebrain is where sensory perception takes place, consciousness resides, and voluntary activities are controlled.

Optimised for size and weight

“Birds not only have a generally higher density of neurons (nerve cells) in the brain than mammals — especially in parrots and corvids — these are also strongly concentrated in the forebrain,” said Tecumseh Fitch of the University of Vienna, who was involved in the study, in an interview with the news agency APA.

In humans and other mammals, the proportion of nerve cells in the cerebellum is comparatively larger, as this is where movement sequences are coordinated, for example.

In the course of evolution, the structure of bird brains was probably optimised for size and weight because they needed to be as light as possible to fly well, the researchers explain in their paper. In any case, “brainpower” is more concentrated in bird brains than in those of mammals, they conclude.

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