This song was written by Leon René, who also composed the Jazz standard "When It's Sleepy Time Down South
" and "Rockin' Robin
," which was a hit for both Bobby Day and Michael Jackson.
René was based in Los Angeles, and about 50 miles away from San Juan Capistrano, where a flock of swallows famously returns to a mission church every March, departing in October. René built the return of the swallows into the storyline of the song, as his heartbroken singer prays for the return of his love, who had promised that she would come back with the swallows, but never did.