duck hawk vs falcon

duck hawk

noun
  • peregrine falcon (Falco peregrinus) 

falcon

noun
  • Any bird of the genus Falco, all of which are birds of prey. 

  • A female such bird, a male being a tiercel. 

  • A light cannon used from the 15th to the 17th century; a falconet. 

verb
  • To hunt with a falcon or falcons. 

How often have the words duck hawk and falcon occurred in a corpus of books? (source: Google Ngram Viewer )