old man's pepper vs popinjay

old man's pepper

noun
  • Achillea millefolium or common yarrow, a flowering plant native to temperate regions of the Northern Hemisphere. 

popinjay

noun
  • The green woodpecker, Picus viridis. 

  • A parrot. 

  • A target to shoot at, typically stuffed with feathers or plumage. 

How often have the words old man's pepper and popinjay occurred in a corpus of books? (source: Google Ngram Viewer )