The orchestra is performing the William Tell overture, but then Donald Duck (in his third appearance in a Mickey cartoon) appears selling ice-cream. Uninvited, Donald takes out his flute and distracts the band into playing Turkey in the Straw.
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Bluegrass, "Turkey in the Straw" is a well-known American folk song dating from the early 19th century. The song's tune was first popularized in the late 1820s and early 1830s by blackface performers, notably George Washington Dixon, Bob Farrell and George Nichols. Another song, "Zip Coon", was sung to the same tune. This version was first published between 1829 and 1834 in either New York or Baltimore.