"Why birds are smart
In Australia, sulfur-crested cockatoos learned to open household waste bins with individual style and site-specific differences (Figure 1C). This culture rapidly spread via social learning to 44 Sydney suburbs, thereby forcing people to develop a counterculture of technical measures to prevent pilfering.
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A detailed comparison of studies in eight cognitive domains concluded that corvids, parrots, and non-human primates possess similar domain-general cognitive capacities.
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Using the Primate Cognition Test Battery to study cognitive development, it could be demonstrated that ravens perform on par with orangutans and chimps, except for spatial skills.
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Here, it seems that all avian species tested to date use mental algorithms similar to mammals, whether corvid, parrot, chicken, or pigeon [...] Corvids go through cognitive developmental steps of object permanence identical to those of children and make the same errors when tested before they have reached a certain stage [...]. Domestic chicks prefer a left-to-right orientation of ascending numerosities – the mental number line – like adult human subjects and newborn babies.
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Taking these findings together, birds and mammals utilize similar mental algorithms when working on cognitive tasks. Within the avian clade, corvids and parrots reach levels of cognitive performance throughout all domains that match those of great apes.
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Around 50 000 years ago, 600-kg dromornithids were the largest birds that ever roamed the Earth but had brains of only 123 g, about one-third of a chimpanzee brain. Corvids and parrots have brains of just 1–25 g. How could these birds become so smart with walnut-sized brains?
A landmark study showed that bird brains contain twice as many neurons per unit brain volume as primates and up to four times more than rodents. Since neurons are the computational processing unit of brains, more neurons per gram brain should produce more processing capacity.
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So, do large pallial neuron numbers explain the similar cognitive capacities of corvids, parrots, and great apes? Not quite. [...] High neuron densities and a higher proportion of pallial neurons reduce the quantitative gap between birds and primates without closing it.
However, birds have one more card up their sleeves. Experience-dependent flexible cognition may be especially related to the number of associative neurons that are situated between sensory and motor systems. It was demonstrated that crow species have a selectively greater number of neurons in their associative pallial areas than chickens, pigeons, and ostriches."
via @moritz_negwer
