In a recent study titled, "Crows 'count' the number of self-generated vocalizations" published in the journal Science, researchers at the University of Tübingen in Germany recount their observations of carrion crows counting out loud.
Crows, like all corvids, are notoriously clever creatures. But this experiment marks the first time scientists have observed the birds engaging in cognitive practices that are not unlike those of a human toddler. From the university press release:
The birds were given the following task: on seeing a selection of Arabic numerals or on hearing specific sounds they had to produce one to four calls as appropriate and then conclude their call sequence by pecking on an enter key. "All three birds succeeded in this. They were able to count their calls in sequence," says [Professor Andreas] Nieder [from the Institute of Neurobiology at the University of Tübingen]. The response time between presentation of the stimulus and emitting the first call in the answer was relatively long and became longer the more calls were required. The length of the delay was unaffected by the nature of the stimulus, visual or auditory. "This indicates that, from the information presented to them, the crows form an abstract numerical concept which they use to plan their vocalizations before emitting the calls," Nieder explains.
[…]
The ability to produce a volitional number of vocalizations demands a highly-developed combination of numerical competence and vocal control. "Our results show that humans are not the only ones who can do this. In principle it also opens up sophisticated communication to the crows," says Nieder.
Also, like a human toddler, the counting crows were not without errors — but the fact that they could control their voices enough to indicate some intention or awareness of a numerical sequence is still pretty interesting.
Previously:
• Build a Crowbox kit and become friends with your neighborhood crows
• Crows Birds stealing coins from car wash?
• How to befriend your neighborhood crows
• I enjoyed reading the post-apocalyptic superhero series 'Murder of Crows'
• Crows can count and they do it out loud
