tattler vs whistle-blower

tattler

noun
  • One who tattles (notifies authorities of illicit behavior) or is inclined to do so; a tattletale. 

  • Either of two similar bird species in the shorebird genus Heteroscelus (Tringa in some taxonomies). 

  • A device fitted to a vehicle to measure mileage etc. 

whistle-blower

noun
  • One who reports a problem or violation to the authorities; especially, an employee or former employee who reports a violation by an employer. 

How often have the words tattler and whistle-blower occurred in a corpus of books? (source: Google Ngram Viewer )