Crows are incredibly intelligent animals. Scientifically known as the genus Corvus, with many subsidiary species around the globe, these birds frequently impress scientists and amateur bird watchers alike with their brilliance. One rescued crow visited his savior every day to sip coffee, while researchers have uncovered crows’ understanding of water level displacement. They can play ball and solve puzzles. While it has long been known that crows can count and even understand the concept of zero, it now appears crows can count out loud. This shocking ability to vocalize numbers was announced in a paper in Science. To investigate whether crows can count out loud, researchers under Diana Liao chose three carrion crows to experiment with. They trained these clever birds to vocalize in response to distinct random noises. Hearing each one, the bird learned to associate that noise with a certain number of caws. The team was trying to replicate the counting out loud that young toddlers do before fully grasping numbers—pointing at objects and calling them out in succession. Even if the numbers they say are wrong, the total number of vocalizations is correct. However, the researchers became concerned that the crows were just gaming the vocalizations for treats without truly “counting.”

Instead, they combined the triggers—noise and visual—with a button. After making the correct number of vocalizations, the crow had to decide when it was done and “submit” its answer to check if it got a treat. The crows did shockingly well, counting their caws to get the right number for each trigger. They mostly got it right, and their errors were only one-offs mostly. “We show that crows can count vocally, which mirrors this important developmental stage in toddlers,” Liao told NPR. Pauses before responses were longer for longer series of vocalizations, which the team hypothesizes might be the bird taking a beat to plan its response. The ability of crows to verbally tally and control the numbers they vocalize is the first instance of this ability demonstrated outside of humans, a shocking discovery and another feather in the cap of a brilliant bird.