It is not uncommon to play with toddlers by raising a certain number of fingers on a hand and asking them to tell the number. A group of scientists tried the trick with crows.

The results amazed them. Crows can count.

Well, the scientists — led by neuroscientist Diana Liao of the University of Tubingen, Germany — didn’t exactly put up their fingers, but trained the crows with visual and auditory cues, making the connection between what they saw and what they heard (like four objects and four sounds, for number 4). The birds would produce a certain “vocalization” for each number (up to 4). They were trained to peck at an “enter button” to signify they were done. If they picked the number correctly, they were given a treat.

After 160 sessions of training the students passed the exam. They did produce a different vocalization for each number, showing they could recognize the numbers, says their paper published in Science.

This is not the first time that the university is researching crow intelligence — its researchers had done it at least once earlier, in 2015. But in this study, scientists have shown that the birds can count aloud, producing a different sound for a different number.

These studies show that crows can count, rather than understand “less” and “more”.