Researchers have found that crows can indeed count to an extent — an ability comparable to those of human toddlers. Specifically, crows can vocalize the number of objects they see, similar to how young children learn to count sequentially by doing so aloud (one, two, three). This awesome discovery sheds new light on avian intelligence and cognitive evolution.

Experimenting with Avian Numeracy

To be clear, we’re not talking about symbolic counting, where numbers are associated with a particular symbol. For instance, 1 + 2 = 3 is a symbolic mathematical operation and this capability is uniquely human.

However, other animals are known to be able to count and solve basic math puzzles. Bees famously can not only count but also grasp the concept of zero. Meanwhile, what Diana Liao, a postdoctoral researcher in neurobiology at the University of Tübingen in Germany, and colleagues found about crows sounds even more impressive.

Crows count by controlling the number of vocalizations they produce. This mirrors the way young children often respond to counting tasks. For example, a toddler might respond to the question “How many apples?” with “One, one, one” or “One, two, three,” producing sounds that correspond to the number of objects they see.

Previous studies hinted at vocalized animal counting abilities, such as in the Black-capped Chickadees. These birds were found to produce more distinct notes at the end of their alarm calls when confronted with a certain predator — the smaller the predator, the more notes they made. However, these findings were inconclusive as they could be attributed to emotional responses rather than intentional counting. Liao’s team sought to clarify this by conducting controlled experiments with three carrion crows (Corvus corone).

The crows were presented with various cues, both visual (colored Arabic numbers on a touch screen) and auditory (a guitar chord or a drumroll). There were four cues for each type of stimulus. Through trial and error, the birds learned to associate the correct number of vocalizations with each cue — from one to four — receiving a reward if they succeeded. If they failed, they had to take a break from the game. When the crows were done counting, they pecked a target to indicate completion.

After extensive training sessions, all crows demonstrated the ability to produce the correct number of calls more often than by chance. They even exhibited the numerical distance effect, where they were more likely to confuse similar numbers, such as three and four.

Four is not a hard limit for the crows; it just so happened that that was the limit of the study’s design. The researchers are confident that crows can count higher than four.

“Producing a specific number of vocalizations with purpose requires a sophisticated combination of numerical abilities and vocal control,” wrote the neuroscientists in their study.

“Whether this capacity exists in animals other than humans is yet unknown. We show that crows can flexibly produce variable numbers of one to four vocalizations in response to arbitrary cues associated with numerical values.”

That’s not all that surprising. Crows have long been recognized as some of the most intelligent birds on the planet.

Crows are innovative tool makers. They’ve been caught using sticks to fish out tasty grubs from hidden nooks and can even bend wires to create makeshift hooks – a feat that requires planning and understanding of object manipulation.

Problem-solving is another crow superpower. These brainy birds can think ahead, storing food for times of scarcity. Some crows have been seen strategically dropping nuts on busy roads. The passing cars then crack open the shells, providing the crows with a delicious, ready-made meal.

Crows aren’t easily forgetful either. They possess an impressive memory, particularly for faces. You better not wrong a crow, for these birds can recognize human faces and hold grudges against those who’ve caused them harm – for years to come!

Communication is another area where crows excel. Their complex vocal repertoire allows them to share information with remarkable precision. Different calls can warn fellow crows of approaching danger or even identify specific individuals within their social group.

Evolutionary Implications

The latest research adds another layer to the crow’s impressive intellectual resume – counting.

“The findings suggest that the birds are capable of using a non-symbolic approximate number system, showing a level of vocal control that mirrors the early counting skills of human toddlers,” the researchers wrote in their study.

The findings have significant implications for our understanding of cognitive evolution. Birds (basically dinosaurs) and mammals diverged about 324 million years ago. The counting abilities observed in crows and mammals must represent convergent evolution, where both groups independently developed similar cognitive solutions.

As such, this research not only highlights the advanced intelligence of crows but also offers insights into the evolutionary pathways of cognition.

The findings appeared in the journal Science.