common bullfinch vs red-backed shrike

common bullfinch

noun
  • A small bird, the Eurasian bullfinch (Pyrrhula pyrrhula). 

red-backed shrike

noun
  • A medium-sized bird (Lanius collurio) of the shrike family that breeds in most of Europe and western Asia and winters in tropical Africa, eating large insects, small birds, voles, and lizards. 

How often have the words common bullfinch and red-backed shrike occurred in a corpus of books? (source: Google Ngram Viewer )