and the crows had to count them by pecking. ANDREAS NIEDER: They can see three dots and then produce three pecks and then press an enter key sort of in order to tell us that they're done with the ...

In one study, for example, a computer screen showed crows a certain number of dots, and the crows had to count them by pecking. ANDREAS NIEDER: They can see three dots and then produce three pecks and ...