flittermouse vs flying mouse

flittermouse

noun
  • A bat (flying mammal). 

flying mouse

noun
  • Any species of rodent in the genus Idiurus, native to parts of tropical Africa, which have the ability to glide. 

  • An input device like a mouse that can be lifted from a surface and moved in three dimensions. 

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