moorhen vs vixen

moorhen

noun
  • A female red grouse, Lagopus lagopus scotica. 

  • Any of various medium-sized water birds of the genus Gallinula, of the rail family, that feed in open water margins. 

vixen

noun
  • A female fox. 

  • A malicious, quarrelsome or temperamental woman. 

  • A racy or salacious woman who is sexually attractive. 

  • A wife who has sex with other men with her husband's consent. 

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