jungle drums vs rumor mill

jungle drums

noun
  • An informal network of news and gossip; the grapevine. 

  • Drumming performed, or as performed, in the rituals of traditional pre-industrial societies. 

rumor mill

noun
  • A process in which a group or network of persons originate or promulgate gossip and other unsubstantiated claims. 

How often have the words jungle drums and rumor mill occurred in a corpus of books? (source: Google Ngram Viewer )