Crows

The Feathered Einsteins

Crows have always been considered clever, but their intelligence might exceed our expectations. Over the past few decades, research on corvids, which are stout-billed birds like crows, jays, magpies, and ravens, has grown significantly. We have discovered that crows utilize traffic to crack tough nuts and can successfully tackle complex puzzles by following a series of steps.

In fact, recent findings indicate that they possess intelligence comparable to that of a seven-year-old child. Furthermore, crows observe us closely, eagerly seeking to learn more about humans.

Hooded crow at the garden of Belvedere, Vienna

In one study at Max Planck Institute for Evolutionary Anthropology, scientists presented the crows with a task where they had to figure out how to retrieve floating food rewards by placing heavy objects into water-filled tubes. Remarkably, the crows demonstrated their ability to select objects that would sink and were solid, rather than hollow. They also showed a preference for the tube that required the least effort to access the food.

According to a 2012 study conducted by the University of Cambridge, the same task posed a significant challenge for children. While children between the ages of seven and ten were able to learn the rules after a few attempts, children aged four to six struggled to solve the problem. Therefore, the crows’ performance matched that of seven- to ten-year-old children who have been successful in completing similar tasks.

In this clip from the BBC TV series, Inside the Animal Mind, Chris Packham watches a New Caledonian crow, nicknamed 007, solve an artificially constructed puzzle involving eight distinct steps.

Crows have remarkable memory for human faces. They can hold grudges and even share this information with other crows. It appears that they understand the uniqueness of each person and the need to approach us differently.

In 2011, researchers at the University of Washington trapped, banded, and released 15 crows. They wore identical “dangerous” masks during the process. Afterward, they observed crow behavior for five years by walking specific routes that included trapping sites. During these observations, some observers wore neutral masks, while others wore the same dangerous masks used during trapping.

In the initial two weeks after trapping, 26% of the crows scolded the individual wearing the dangerous mask. Approximately 15 months later, this percentage rose to 30.4%. After three years, the number of scolding crows increased to 66%. Evidently, the crows communicate among themselves, sharing knowledge about the perceived threat.

In the wild, New Caledonian crows use their tools to scoop insects out of holes, for example in tree trunks.

Clever primates, including humans, possess a brain structure known as the neocortex, which is believed to support advanced cognition. In contrast, corvids, such as crows, lack this structure. Scientists have discovered that crows engage in thinking within the pallium, the layers of gray and white matter that cover the upper surface of the cerebrum in vertebrates.

Recent research reveals that birds have smaller and densely packed neurons, a feature that aids in reducing weight and facilitating flight. Surprisingly, crows possess a similar number of neurons (approximately 1.5 billion) to certain monkey species. However, due to their tighter arrangement, the communication between these neurons appears to be more efficient.

Consequently, crows’ overall intelligence may approach that of Great Apes like gorillas. Furthermore, it is noteworthy that a crow’s brain constitutes nearly 2% of its body mass, a proportion comparable to that of humans.