chirr vs scritch

chirr

noun
  • The trilled sound made by an insect. 

verb
  • To make the prolonged trilling sound of an insect (e.g. a grasshopper, a cicada). 

scritch

noun
  • A light scratching sound, like a small animal burrowing. 

  • The act of scratching an itch. 

verb
  • To scratch so as to relieve an itch or irritation. 

  • To make a light scratching sound, like a small animal burrowing. 

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