Have MP3s killed the art of whistling?
10 March 2011 Last updated at 09:07 GMT
What is a more common sound - the chirp of someone whistling or the muffled beat of someone's music from their earphones?
World Champion whistler David Morris thinks his skill is a dying art and blames the personal music player.
Is he right?
Sophie Van Brugen reports.
Pictures: British Pathe