cock pigeon vs turtle dove

cock pigeon

noun
  • A male pigeon. 

turtle dove

noun
  • Any of several (species of) birds, called by this traditional name, mainly in the genus Streptopelia, of the family Columbidae (doves and pigeons, which also included the extinct passenger pigeon, dodo, and solitaire). 

How often have the words cock pigeon and turtle dove occurred in a corpus of books? (source: Google Ngram Viewer )