“My Name is Nobody”: Soundtrack for a Cipher

I would love to know exactly how Ennio Morricone instructed his vocalists to yip and mew and emit all sorts of silly sounds, as on the title track to the 1973 Sergio Leone film,            Il Mio Nome è Nessuno (My Name Is Nobody):

Vimeo lists musician credits for this soundtrack album – including a whistler, I love it:

Voice: Edda Dell ‘Orso & Franco Cosacchi

Whistle: Alessandro Alessandroni

Choir:  I Cantori Moderni Di Alessandroni

Flute: Marianne Eckstein

Mouth Organ: Franco De Lelio

Trumpet: Gino Agostinelli

Guitar: Bruno Battisti D’Amario

12 Strings Guitar: Silvano Chimenti

Piano & Keyboards: Arnaldo Graziosi

Synthesizer: Giorgio Carnini

Percussions: Vincenzo Restuccia

Il Mio Nome e Nessuno album cover