birder vs naturalist

birder

noun
  • A person who hunts birds. 

  • A birdwatcher. 

naturalist

noun
  • An expert in natural history or the study of plants and animals. 

  • A person who believes in or advocates the tenets of philosophical or methodological naturalism. 

  • A creative artist who attempts to faithfully represent nature; an adherent of artistic naturalism. 

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