erne vs fish eagle

erne

noun
  • A sea eagle (Haliaeetus), especially the white-tailed eagle (Haliaeetus albicilla) 

  • An eagle. 

fish eagle

noun
  • Any of several species of birds of prey that feed on fish in the genus Haliaeetus (syn. Ichthyophaga). 

  • The osprey (Pandion haliaetus). 

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