Birds are far from stupid.

Some can solve problems, recognize themselves in mirrors, and plan for the future–activities that go well beyond instinct.

That’s why their lack of a neocortex—the area of the mammalian brain where working memory, planning, and problem-solving happen—has long baffled scientists.

A new study by researchers at Ruhr-University Bochum (RUB) in Bochum, Germany, may provide some clues to help explain that mystery.

Using 3D polarized light imaging and miniature crystals, the team found startling similarities between the neocortex in mammals and the corresponding sensory brain areas of birds. This high-resolution technique allowed them to analyze the circuitry of a forebrain region in birds called the pallium, which is considered similar to the neocortex in mammals. The scientists then compared the images of the birds’ pallia with those of rat, monkey, and human cortices.

Their analysis revealed the fibers in the birds’ pallia are organized in a manner strikingly similar to those of fibers in mammal cortexes. Both, it turns out, are made up of horizontal layers and vertical columns, and both transmit signals from top to bottom and back again. In fact, birds may have a higher degree of connectivity between different parts of their brains than some mammals do.

“Considering the astonishing cognitive performance that birds can achieve, it seemed reasonable to suspect that their brains are more organized than expected,” said coauthor Onur Güntürkün, PhD, head of the Biopsychology Research Unit at RUB.

In other experiments, the researchers examined the interconnection of cells in the bird brain in detail. “Here, too, the structure was shown to consist of columns, in which signals are transmitted from top to bottom and vice versa, and long horizontal fibers,” said Güntürkün.

It’s this neuroarchitecture—the connections between structures, rather than the structures themselves—that explains why birds are as cognitively talented as mammals, the researchers say.

Of course, some birds—like some mammals—are smarter than others. Ornithologists say that parrots and corvids—such as ravens, crows, and jays—are some of the most intelligent birds.

In a New Zealand study, pigeons proved capable of learning English. Some of them were able to learn to spell as well as a six-year-old child.

It gives a whole new meaning to the phrase “bird brain.”

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