churr vs rattling

churr

noun
  • A low vocal sound made by some birds. 

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

rattling

noun
  • rattle (a sound made by loose objects shaking or vibrating against one another) 

adj
  • Lively, quick (speech, pace). 

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