bird dog vs convoy

bird dog

verb
  • A multiservice tactical brevity code requesting configuration of sensors. 

  • To seek out. 

  • 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. 

convoy

verb
  • To escort a group of vehicles, and provide protection. 

  • To travel under convoy. 

noun
  • The act of convoying; protection. 

  • A group of vehicles travelling together for safety, especially one with an escort. 

  • One or more merchant ships sailing in company to the same general destination under the protection of naval vessels. 

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