songbird vs troubadour

songbird

noun
  • Any bird in the passerine suborder Passeri, which are distinguished by a more sophisticated vocal apparatus 

  • A bird having a melodious song or call. 

troubadour

noun
  • An itinerant composer and performer of songs in medieval Europe; a jongleur or travelling minstrel. 

How often have the words songbird and troubadour occurred in a corpus of books? (source: Google Ngram Viewer )