bird of passage vs social butterfly

bird of passage

noun
  • Someone passing through a place and only staying for a short time; an itinerant. 

  • A migratory bird, especially a passage migrant (“a bird that stops somewhere for a short time during a seasonal migration”). 

social butterfly

noun
  • A gregarious person who likes to attend parties and other social gatherings; a people person. 

How often have the words bird of passage and social butterfly occurred in a corpus of books? (source: Google Ngram Viewer )