Jim Henson - Run, Run

From Muppet Wiki:
Run, Run is a short film produced by Jim Henson and Muppets Inc. in 1965. The 4-minute film was shot by Jim Henson and Frank Oz at Henson's Greenwich, CT home in late October of 1965, and featured Henson's family.
The film focuses on two children (Henson's daughters Lisa and Cheryl) cavorting in the woods, surrounded by autumn leaves, until they reunite with their mother. The score by Joe Raposo (similar to his later film insert songs and scores for Sesame Street) includes female vocals (no specific lyrics, just mood "da das") and whistles.