dotterel vs nitwit

dotterel

noun
  • A gullible fool, especially an elderly person with impaired faculties. 

  • A small brown-and-black bird, Charadrius morinellus, of the plover family. 

  • Any of various small birds of Australasia thought to resemble the Eurasian dotterel. 

adj
  • decayed 

nitwit

noun
  • A scatterbrained or stupid person. 

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