bullfinch vs goldfinch

bullfinch

noun
  • The Eurasian bullfinch (Pyrrhula pyrrhula). 

  • Any of various other Old World finches in the genus Pyrrhula. 

goldfinch

noun
  • The European goldfinch (Carduelis carduelis) 

  • Lawrence's goldfinch (Spinus lawrencei, syn. Carduelis lawrencei) 

  • The lesser goldfinch (Spinus psaltria, syn. Carduelis psaltria). 

  • The American goldfinch (Spinus tristis, syn. Carduelis tristis) 

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