barn owl vs western barn owl

barn owl

noun
  • An owl of the species Tyto alba, often having a white face and commonly found in barns and other farm buildings. 

western barn owl

noun
  • A barn owl of the subspecies Tyto alba alba, endemic to western Eurasia and most of Africa. 

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