great horned owl vs snowy owl

great horned owl

noun
  • A large owl, Bubo virginianus, resident in North America, having tufts on its ears. 

snowy owl

noun
  • A large, white, nomadic Arctic owl, Bubo scandiacus. 

How often have the words great horned owl and snowy owl occurred in a corpus of books? (source: Google Ngram Viewer )