 For some species, this call consists of a short, high-pitched sound, recognized and duplicated exactly by mates.Some fowl, such as geese,"honk" while in migration to communicate location and proximity to others in their flock.In parapatric and sympatric species of birds, where territories of one species may border or overlap with that of another species, the contact calls of each species may divergently evolve to help differentiate one species from that of the other within close proximity.