these communication sounds are often short hard sounds like: chirps, squeaks, squawks and twitters. sometimes the calls are longer and more musical. they include the "rookety-coo" sound of a pigeon and the "cockadoodledoo!" of a rooster. the bird cannot change these sounds. they always make them in the same way. the bird is locked into making each sound every time a particular idea comes into its head. the connection between how they feel and how they call is innate: they are born with it. some calls in some species are learnt. then, it is the tendency to learn which is inherited.