Enlarge / Sure, they can use tools, but do they know where the nearest subway stop is? (credit: Jonas Adner )

"A thirsty crow wanted water from a pitcher, so he filled it with pebbles to raise the water level to drink , " summarizes a famous Aesop Fable . While this tale is thousands of years old, animal behaviorists still use this challenge to study corvids (which include crows, ravens, jays, and magpies) and their use of tools. In a recent Nature Communications study , researchers from a collaboration of universities across Washington, Florida, and Utah used radioactive tracers within the brains of several American crows to see which parts of their brains were active when they used stones to obtain food from the bottom of a water-filled tube.

Their results indicate that the motor learning and tactile control centers were activated in the brains of the more proficient crows, while the sensory and higher-order processing centers lit up in the brains of less proficient crows. These results suggest that competence with tools is linked to certain memories and muscle control, which the researchers claimed is similar to a ski jumper visualizing the course before jumping.

The researchers also found that out of their avian test subjects, female crows were especially proficient at tool usage, succeeding in the challenge quickly. “[A] follow-up question is whether female crows actually have more need for creative thinking relative to male crows,” elaborates Loma Pendergraft , the study’s first author and a graduate student at the University of Washington, who wants to understand if the caregiving and less dominant role of female crows gives them a higher capacity for tool use.

Enlarge (credit: John Dreyer )

Whether playing tricks, mimicking speech, or holding “ funerals ,” crows and ravens (collectively known as corvids) have captured the public’s attention due to their unexpected intelligence. Thanks to results from a new Current Biology study, our understanding of their capabilities only continues to grow, as researchers from the University of Tübingen found for the first time that crows can perform statistical reasoning. These results can help scientists better understand the evolution of intelligence (and may give us a better appreciation of what’s going on in our backyard).

Bird brains

With a population of over 27 million and counting, crows seem almost ubiquitous across the US. Their loud “caws” are hard to miss, and the tone of these cries varies depending on what the birds are communicating. Like other corvids, crows have a large brain for their size and a particularly pronounced forebrain , which is associated with statistical and analytical reasoning in humans. Thanks to these attributes, ornithologists and animal behaviorists have found crows doing various “intelligent” activities, such as using twigs as tools to extract bugs from tree bark. Some experts have even classified corvids as having the same intelligence as a 7-year-old child.

Beyond using tools, corvids can also do basic mathematical functions, like adding or subtracting. “In the scheme of the natural world, very few animals are demonstrated to possess much in the way of mathematical intelligence (beyond basic numerical discrimination)—things like numerical competence, an understanding of arithmetic, abstract thinking, and symbolic representation,” explained Dr. Kaeli Swift, a postdoctoral researcher in bird behavior at the University of Washington (she was not involved in the Current Biology study). “That several corvid species have been demonstrated to possess some of these skills makes them quite special.”

instructions