Crows are able to count.

Crows can count to four

Crows can count to four

Experts have discovered that the clever birds have a basic understanding of numbers on a similar level to human toddlers.

The researchers have found that the birds are able to control the number of vocalisations they produce and can 'count' to four in response to cues.

The skill to count out loud requires numerical knowledge and vocal control, a complex ability that is developed in childhood by human beings.

A team of researchers at the University of Tubingen in Germany said: "Producing a specific number of vocalisations with purpose requires a sophisticated combination of numerical abilities and vocal control.

"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 vocalisations in response to arbitrary cues associated with numerical values."