He performs the Adagio and Rondo movements of the Mozart Flute Quartet in D, and you can feel the regulars tighten to alertness. A member of the Washington Chorus, Barreto has very good pitch and intricate phrasing. Hider hotly denies that people don't whistle much anymore. What you don't hear is whistling in popular music, because there is less attention to melody. It's just personal, and private.
People do it for themselves, to validate or acknowledge their existence.
Whistling is language in villages in Mexico, Turkey, Africa and Guatemala. Natives of La Gomera in the Canary Islands insist their children learn El Silbo, the whistling language from aboriginal times, so it doesn't get drowned out by the cell phone and Internet. In China, whistling is used in toilet training, as a mother's signal for appropriate times to participate. But the academics fall silent when faced with whistling as music, leaving ample room for the form's detractors. No great or successful man ever whistles.