hobby vs kestrel

hobby

noun
  • Any of four species of small falcons in the genus Falco, especially Falco subbuteo. 

  • An activity that one enjoys doing in one's spare time. 

  • An extinct breed of horse native to the British Isles, also known as the Irish Hobby 

kestrel

noun
  • Any of various small falcons of the genus Falco that hover while hunting. 

  • The common kestrel, Falco tinnunculus. 

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