The brains of birds are a bit of a mystery. Despite the little size of their brains, parrots and corvids exhibit exceptional intellect, solving some problems just as effectively as primates.
Previous research has shown that the forebrains of songbirds and parrots have a huge number of neurons, sometimes even more than those of monkeys.
The assumption that cognitive capacity is related to the overall number of neurons in an animal seems intuitive, but it lacks substantial proof.
A recent assessment of apes, corvids, and pigeons revealed that overall neuron counts are a poor predictor of absolute cognitive capacity, yet they may account for an animal’s learning speed or adaptation to settings.
Other research differ. Their results indicate that the overall number of neurons in the pallium, a particular region of the bird’s forebrain, does influence memory, learning, reasoning, and problem-solving.
However, what numbers should we count? The relative or absolute amount of neurons? In other words, does having a large body make a bird intelligent? Or is it all about the size of their brain relative to their body?
A team of academics now believes it is a compromise between the two, which was previously ignored.
The authors began by estimating the number of neurons present in the palliums of 111 bird species. Then, scientists compared these figures to more than 4,400 novel methods in which birds use food or feed.
In the end, scientists discovered that bird species with a greater number of neurons in their pallium were more likely to be inventive.
However, when there were more neurons in the pallium, there were often fewer neurons in other regions of the brain.
“If a bird’s forebrain includes a disproportionately high number of neurons, this should create a brain that is both bigger in absolute terms and proportional to its body size,” conclude the scientists.
The results show that a “disproportionate allocation of neurons to cognitive activities” contributes to the intelligence of birds.
As a result, the authors assert that their data support the concept that intelligence is dependent on both the overall number of neurons and the manner in which these neurons link various brain regions.
In summary, evaluating intelligence is far more involved than just counting neurons or identifying the cell density in a specific location.
Instead, the authors believe that bird intelligence is related to the management and integration of the brain’s widely scattered networks.
The authors add, “This final observation supports the assumption that animals with huge brains just because they have large bodies are not always the most intelligent.”
When comparing the development of all the bird species in their study, researchers discovered that those species that grow more slowly as fledglings had a greater number of neurons in their pallium.
This shows that increased intelligence in birds may need an additional period of brain development after hatching, during which the pallium is enlarged.
Biologist Louis Lefebvre from McGill University in Canada suggests that the amount of time fledglings spend in the nest as their brains grow may also play an important role in the development of intelligence.
Larger species of crows and parrots, who are recognised for their intelligence, spend more time in the nest, which gives the brain more time to develop and collect pallial neurons.
Comparatively, human development is comparable to that of chimpanzees and bonobos. Our brains are three times the size of those of other primates, yet we mature far more slowly.
Recent brain research reveals that our intellect is better to that of other primates not because our brains are larger, but because they are more flexible and exhibit more synergy.
The same may also be true with birds.
What makes certain animal species more intelligent than others is still a mystery to scientists. So, until we learn more, it may be prudent to refrain from mocking the size of avian brains.