bird dog vs eyewitness

bird dog

verb
  • To watch closely. 

  • A multiservice tactical brevity code requesting configuration of sensors. 

  • To seek out. 

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. 

eyewitness

verb
  • To be present at an event, and see it 

noun
  • Someone who sees an event and can report or testify about it. 

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