partridge vs red-legged partridge

partridge

noun
  • Any bird of a number of genera in the family Phasianidae, notably in the genera Perdix and Alectoris. 

red-legged partridge

noun
  • Any partridge of species Alectoris rufa. 

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