fishhawk vs osprey

fishhawk

noun
  • The osprey. 

osprey

noun
  • aigrette (ornamental feather) 

  • A bird of prey (Pandion haliaetus) that feeds on fish and has white underparts and long, narrow wings each ending in four finger-like extensions. 

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