bird dog vs shake down

bird dog

verb
  • To seek out. 

  • A multiservice tactical brevity code requesting configuration of sensors. 

  • To watch closely. 

noun
  • A dog, especially a pointer, used in shooting to retrieve the dead birds. 

  • A tout. 

  • A person who seeks out real estate investment opportunities in exchange for a fee. 

  • A person who tries to steal someone else's romantic partner 

  • A radar detector (for detecting police speed traps). 

  • A hyperextension exercise performed lying on the knees, with one arm and the opposite leg lifted. 

shake down

verb
  • To search exhaustively. 

  • To shake someone so money falls from their pockets. 

  • To cause something to fall down by shaking it, or something it is attached to. 

  • To extort money from (someone) by means of threats. 

  • To subject something to a shakedown test. 

How often have the words bird dog and shake down occurred in a corpus of books? (source: Google Ngram Viewer )