heron vs red-crowned crane

heron

noun
  • A long-legged, long-necked wading bird of the family Ardeidae. 

red-crowned crane

noun
  • Grus japonensis, a bird of the crane (Gruidae) family, native to East Asia 

How often have the words heron and red-crowned crane occurred in a corpus of books? (source: Google Ngram Viewer )