Crows can understand probability like primates do

Crows can make decisions according to the likelihood of getting a reward – a cognitive feat known to mathematicians as statistical inference, and rarely found outside of primates.

“‘Bird brain’ is often used as an insult, but that’s not really the case,” says Melissa Johnston at the University of Tubingen in Germany.

Her team trained two carrion crows (Corvus corone) to peck at nine, different-coloured symbols to receive a reward: a small food pellet or worms. Each symbol was associated with a different probability of receiving …