diva vs songbird

diva

noun
  • A person who may be considered or who considers herself (or by extension himself) much more important than others, has high expectations of others and who is extremely demanding and fussy when it comes to personal privileges. 

  • Any female celebrity, usually a well known singer or actress. 

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. 

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