faeces vs guano

faeces

noun
  • UK, Canada, Ireland, South Africa, Australia, and New Zealand standard spelling of feces. 

guano

noun
  • Coccothrinax borhidiana, a variety of palm tree indigenous to Cuba. 

  • Dung from a sea bird or from a bat. 

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