feral cat vs kitten

feral cat

noun
  • A domestic cat that has returned to or was born in a living situation without human care. 

kitten

noun
  • A young cat, especially before sexual maturity (reached at about seven months). 

  • A moth of the genus Furcula. 

  • A young rabbit, rat, hedgehog, squirrel, fox, beaver, badger, etc. 

  • A term of endearment, especially for a woman. 

verb
  • To give birth to kittens. 

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