lovebird vs turtle dove

lovebird

noun
  • Any small parrot from one of the nine species within the genus Agapornis. Sometimes they are kept as cage birds and are noted for their affection towards each other. 

  • One of the members of an openly affectionate couple. 

verb
  • To express romantic affection openly. 

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 lovebird and turtle dove occurred in a corpus of books? (source: Google Ngram Viewer )