Parrots and cockatoos are very intelligent. Ravens and crows are really smart, too. Magpies, macaws, jays and parakeets ... all brilliant birds. But how is it that these avian animals are so clever when their brains are relatively small? After all, isn't it our big brains relative to our body size that makes us humans so amazingly smart? Turns out, not necessarily.
A study conducted by University of Alberta researchers analyzed the brains of 98 birds — all the way from chickens to parrots — and discovered that birds have a medial spiriform nucleus (SpM), which circulates information between the cortex and cerebellum. "This loop between the cortex and the cerebellum is important for the planning and execution of sophisticated behaviors," said Doug Wylie, professor of psychology and co-author on the study, which was published in Scientific Reports.
Out of all the birds, parrots seem to come out on top when it comes to intelligence. Scientists analyzed the size of the birds' SpM compared to the rest of their brain and learned that parrots have a larger SpM compared to others. "Independently, parrots have evolved an enlarged area that connects the cortex and the cerebellum, similar to primates," said Cristian Gutierrez-Ibanez, postdoctoral fellow at University of Alberta. "This is another fascinating example of convergence between parrots and primates. It starts with sophisticated behaviors, like tool use and self-awareness, and can also be seen in the brain. The more we look at the brains, the more similarities we see."
Earlier research also shows that birds pack a ton of neurons in the forebrain, which means they make the most of those small brains for maximum cognitive ability. In fact, they have more neurons per square inch than mammals, including primates.
In a study published in the Proceedings of the National Academy of Sciences, the researchers write:
"We investigated the cellular composition of the brains of 28 avian species, uncovering a straightforward solution to the puzzle: brains of songbirds and parrots contain very large numbers of neurons, at neuronal densities considerably exceeding those found in mammals. Because these "extra" neurons are predominantly located in the forebrain, large parrots and corvids have the same or greater forebrain neuron counts as monkeys with much larger brains. Avian brains thus have the potential to provide much higher "cognitive power" per unit mass than do mammalian brains."
This explains why many bird species show levels of intelligence equally as high as that of primates. It opens up a whole new way of understanding how brains have evolved and what "smart" looks like under a microscope.
Check out the video below and you'll start thinking differently about birds, even the humble pigeon!
Editor's note: This article has been updated since it was originally published in June 2016.