chaffinch vs goldfinch

chaffinch

noun
  • A small passerine bird, Fringilla coelebs, of the finch family, found throughout Europe and eastward to Iran and eastern Mediterranean coastlands. 

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 chaffinch and goldfinch occurred in a corpus of books? (source: Google Ngram Viewer )