Related Clues:

• Billboard entry
• Warbler's gift
• 'Yesterday' or 'Tomorrow'
• Adjust to the correct pitch
• Whistler's production
• Hit, maybe
• Musical setting
• Adjust, as strings
• 'Yesterday,' 'Today' or 'Tomorrow'
• Choral performance
• Balladeer's number
• Something whistled
• Thing that may be streamed
• Common digital download
• It may have a nice melody