Crows Demonstrate Remarkable Counting Abilities Comparable to Young Children, Researchers Find

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Recent research has revealed that crows, often seen as urban birds, have the ability to vocally count up to four. Maybe being "birdbrained" isn't such a bad thing after all!

A new study led by a team of researchers from the University of Tübingen’s animal physiology lab in Germany has found that inquisitive creatures can not only count, but they can also match the number of calls they make when shown a numeral.

The way birds recognize and react to numbers is similar to how humans learn to count as toddlers and quickly recognize the quantity of objects in front of them. These findings, published in the journal Science on Thursday, further contribute to our understanding of crow intelligence.

Animal cognition expert Heather Williams emphasized that humans do not possess exclusive skills such as numerical thinking, abstraction, tool manufacture, and planning ahead. Williams, a biology professor at Williams College in Massachusetts, pointed out that crows are known for being intelligent creatures, and this should not come as a surprise. She was not part of the study.

Counting abilities are not unique to crows in the animal kingdom. Chimpanzees have been taught to count in numerical order and understand the value of numerals, similar to young children. Male frogs, in an attempt to attract mates, are able to count the number of calls from rival males and match or exceed that number when it is their turn to serenade a female. Some scientists believe that ants are able to find their way back to their colonies by counting their steps, although this method may not always be accurate.

What this latest study showed is that crows, like young humans, can learn to associate numerals with values –– and count out loud accordingly.

Can crows count much like toddlers do?

The study was motivated by observing toddlers as they learn to count, according to Diana Liao, a neurobiologist and senior researcher at the Tübingen lab. Toddlers often use number words to count the objects in front of them. For example, if they see three toys, they might count "one, two, three" or "one, one, one."

Eurasian jay / European jay (Garrulus glandarius / Corvus glandarius) perched on tree trunk in forest. (Photo by: Philippe Clement/Arterra/Universal Images Group via Getty Images)

Eurasian jay, also known as European jay, is seen perched on a tree trunk in the forest. The photo was taken by Philippe Clement and is part of the Arterra/Universal Images Group collection.

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Liao was intrigued by the idea that crows could potentially tailor their alarm calls similar to chickadees, as shown in a study from June 2005. The study revealed that chickadees adjusted the number of "dee" sounds in their alarm calls based on the size of the predator they encountered. Larger predators resulted in fewer "dee" sounds, while smaller predators led to more "dee" sounds, indicating potential threat levels for the chickadees.

The authors of the chickadee study were unable to determine if the adjustment in alarm calls was a voluntary action or an involuntary response. This uncertainty led Liao to wonder if crows, known for their intelligence in various research studies, could exhibit similar control over the number of sounds they produce. This raised the question of whether crows could potentially demonstrate a form of "counting" ability, akin to toddlers.

Liao and her colleagues spent over 160 sessions training three carrion crows, a type of bird closely related to the American crow. The goal was for the birds to make associations between visual and auditory cues that represented numbers from 1 to 4. For example, a bright blue numeral might be shown as the visual cue, and the sound of a drumroll could be the corresponding audio cue.

The crows were trained to match the number of caws to the cue they saw – for example, three caws for the number 3 – within 10 seconds. After counting and cawing, they would peck the "enter" key on the touchscreen to confirm they were finished. If they were correct, they received a treat.

As the cues continued, the crows took longer to respond to each one. This delay in reaction time indicated that the crows were planning how many caws to make before vocalizing.

Measured against a typical nectar feeder, the size of the Northern Giant Hummingbird is especially astonishing.

Measured against a typical nectar feeder, the size of the Northern Giant Hummingbird is especially astonishing.

Xiaoni Xu/Macaulay Library/Cornell Lab

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Scientists have solved the mystery of giant hummingbirds with the help of tiny backpacks. The researchers discovered that they could determine how many calls the birds intended to make based on the sound of their first call. This subtle acoustic difference indicated that the birds were aware of the number of calls they needed to make and had processed the information.

Williams explained that crows have the ability to comprehend abstract numbers. They can then strategize and adjust their actions to correspond with the specific number they are presented with.

Even the errors made by the crows were quite sophisticated. For example, if a crow cawed too many times, stumbled over a number, or prematurely submitted their response with their beak, Liao and her team could identify where they went wrong just by listening to the initial call. These mistakes are similar to the ones that humans make, according to Williams.

We are continuously discovering the intelligence of crows.

In the past, it was believed that birds and other animals only made decisions based on immediate stimuli. This theory was promoted by the animal behaviorist B.F. Skinner in the 20th century. However, recent research by Liao and her team indicates that crows can actually use numbers to create a sound, showing that this ability is under their control.

The study team’s findings challenge the common belief that animals are only stimulus-response machines, according to Kevin McGowan, a researcher at the Cornell Lab of Ornithology in Ithaca, New York. McGowan, who has studied wild crows for over two decades, emphasized the significance of the findings.

McGowan, who was not part of the study, explained to CNN that the research showed that crows are not just reactive creatures. Instead, they are capable of thinking ahead and communicating in a structured and preplanned manner. This ability is seen as a crucial step towards developing a language.

For decades, scientists have been studying the intelligence of crows. One interesting study focused on New Caledonian crows, who were observed creating their own compound tools to get food. These birds seem to follow certain rules, as shown in a study from November 2013 led by Andreas Nieder from the University of Tübingen lab. The language of crows has also puzzled scientists for many years, with its wide range of tones and expressions, according to McGowan.

Another study by Liao and her team is not the first to explore whether crows can count. This line of research actually started back in 1968 with Nicholas Thompson, as highlighted by animal cognition expert Irene Pepperberg. Pepperberg, a research professor at Boston University specializing in psychological and brain sciences, is most famous for her work with an African grey parrot named Alex.

Rébecca Kleinberger

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Thompson had a theory that crows could count based on the way they cawed, controlling the duration and number of caws in a burst of sound. He believed that the crows' counting abilities went beyond what was necessary for survival.

In a study conducted by the University of Tübingen in September 2015, crows were trained to recognize groupings of dots. The researchers monitored the activity of neurons in the crows' brains responsible for processing visual information. It was discovered that the crows' neurons focused solely on the number of dots, disregarding factors like size, shape, and arrangement, as stated by the university.

Williams explained that crows have the ability to understand and represent various quantities in their brains. They can also easily learn to associate Arabic numerals with these quantities, a skill that humans typically teach their children explicitly.

Editor's P/S:

The recent discovery that crows can count vocally up to four is a testament to the remarkable cognitive abilities of these birds. This study challenges the traditional view that animals are merely stimulus-response machines and provides evidence that crows can think ahead and communicate in a structured manner. The findings suggest that crows have a higher level of intelligence than previously thought and may even be capable of developing a language.

Crows' counting abilities are similar to how humans learn to count as toddlers. They can recognize and react to numbers, match the number of calls they make to a numeral, and plan how many caws to make before vocalizing. This sophisticated behavior indicates that crows have a deep understanding of abstract numbers and can strategize accordingly. The errors they make are also similar to those made by humans, suggesting that crows may share some cognitive processes with us.