cockerel vs rooster

cockerel

noun
  • A young male chicken. 

rooster

noun
  • A male domestic chicken (Gallus gallus domesticus) or other gallinaceous bird. 

  • A powerful, prideful, or pompous person. 

  • A wild violet, when used in a children's game based on cockfighting. 

  • A bird or bat which roosts or is roosting. 

  • A man. 

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