hart vs wapiti

hart

noun
  • A male red deer or one of related species. 

  • A male deer, especially the male of the red deer after his fifth year. 

wapiti

noun
  • The American elk (Cervus canadensis). It was formerly considered to be in the same species as the European red deer, which it somewhat exceeds in size. 

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