mockingbird vs tui

mockingbird

noun
  • A long-tailed American songbird of the Mimidae family, noted for its ability to mimic calls of other birds. 

tui

noun
  • A species of honeyeater, Prosthemadera novaeseelandiae, a bird which is endemic to New Zealand. 

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