hobby vs sparrow hawk

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 

sparrow hawk

noun
  • The American kestrel or American sparrowhawk (Falco sparverius), a small falcon found in North and South America that preys on grasshoppers and small animals. 

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