MALE - BEAK CHALAUNE HO; FEMALE CHUPCHAP BASNE HO. It's a courtship ritual. He has to sing his best song, otherwise , the girl is going to reject him and go for males with better vocal chords. This is called 'MALE SELECTION'. The girl has to choose the best male amongst thousands of loitering majnus, to mate, to ensure the best genes pass on to her progenys. IN THE PIC ABOVE - THE GIRL IS IGNORING THE BOY'S ADVANCES, WHICH MEANS SHE HAS REJECTED HIM. LOSER!