It has long been suspected that birds (and reptiles) were not very smart because they lack a neocortex – the part of the brain that is responsible for working memory, perception, problem solving, and conscious thought in mammals. In stark contrast to this idea, studies have repeatedly shown that several species of birds have very good memories as well as planning and problem solving skills (see examples below), which has left researchers scratching their own heads trying to figure out how that is possible.
In a new study published yesterday in Science, Dr. Martin Stacho and colleagues from Ruhr-University Bochum decided to examine this apparent contradiction by studying the forebrain of homing pigeons. The specific area they were interested in studying is called the pallium. In comparing the pallium to the cortex of humans, rats and monkeys, they found that the nerve fibers are organized in a similar fashion as the cortex in mammals. They also discovered that the connections between the structures in the pallium are what gives birds similar abilities as mammals to solve problems. In other words, bird brains are actually wired quite similarly to mammals.
To measure consciousness, a separate study published in the same issue of Science conducted by Dr. Andreas Nieder (University of Tubingen) and colleagues examined how the neurons in the pallium of crows respond to visual cues. Birds were trained to either move or remain still when shown a cue. What they found was that neurons in the pallium fired when the birds responded to the cues. The pattern of neuronal firing was seen as evidence that the animals were consciously sensing the visual cues, then reacting – similar to the way primates process and respond to visual cues.
Check out these prior posts on avian intelligence:
JC Eccles. Evolution of consciousness. Proceedings of the National Academy of Sciences USA. 89(16): 7320-7324, 1992.
M Stacho, C Herold, H Wagner, M Axer, K Amunts, O Gunturkun. A cortex-like canonical circuit in the avian forebrain. Science. 369(6511): eabc5534, 2020.
A Nieder, L Wagener, P Rinnert. A neural correlate of sensory consciousness in a corvid bird. Science. 369(6511): 1626-1629, 2020.