churr vs yowl

churr

noun
  • A low vocal sound made by some birds. 

verb
  • To make the low vocal sound of some birds. 

yowl

noun
  • A prolonged, loud cry, like the sound of an animal; a wail; a howl. 

verb
  • Utter a yowl. 

  • Express by yowling; utter with a yowl. 

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