house martin vs martin

house martin

noun
  • A migratory passerine bird of the swallow family, genus Delichon 

  • The common house martin (Delichon urbicum). 

martin

noun
  • Any of various passerine birds of the family Hirundinidae, which also includes swallows, that catch insects whilst flying. 

  • A perforated stone-faced runner for grinding. 

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