falcon vs gyrfalcon

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. 

gyrfalcon

noun
  • Falco rusticolus, a large bird of prey that breeds on Arctic coasts and islands of North America, Europe and Asia. 

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