black francolin vs francolin

black francolin

noun
  • A game bird in the francolin family (Francolinus francolinus, of south and southwestern Asia) 

francolin

noun
  • Any of various terrestrial partridges of several genera in family Phasianidae, principally in tribe Gallini. 

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