bird dog vs protector

bird dog

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

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

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

  • To seek out. 

  • To watch closely. 

protector

noun
  • A device or mechanism which is designed to protect. 

  • A state or other subject under international law, exercising a protectorate over another subject in international law. 

  • One having the care of the kingdom during the king's minority; a regent. 

  • One who prevents interference. 

  • A cardinal, from one of the more considerable Roman Catholic nations, who looks after the interests of his people at Rome; also, a cardinal who has the same relation to a college, religious order, etc. 

  • Someone who protects or guards, by assignment or on their own initiative. 

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