bushchat vs scrub robin

bushchat

noun
  • Any of several African birds in the genus Cercotrichas. 

  • Any of a number of small insect-eating birds in the muscicapid genus Saxicola. 

scrub robin

noun
  • Any of several African birds of the genus Cercotrichas. 

  • An Australian singing bird of the genus Drymodes. 

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