chatterer vs yapper

chatterer

noun
  • A person who chatters; a chatterbox. 

  • Any of several passerine birds, mostly from South America; especially the cotingas. 

yapper

noun
  • One's mouth, especially of a gossipy person. 

  • A dog, especially of a small breed. 

  • One who yaps. 

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