death march vs migration

death march

noun
  • A forced movement of people, on foot, in such circumstances that many die during the journey. 

  • Synonym of dead march (“mournful music for a funeral etc.”) 

  • A project that requires a stretch of unsustainable overwork, or whose participants feel it is destined to fail. 

migration

noun
  • Movement in general. 

  • Instance of changing a platform from an environment to another one. 

  • The movement of cells in particular directions to specific locations. 

  • Seasonal moving of animals, as mammals, birds or fish, especially between breeding and non-breeding areas. 

  • An instance of moving to live in another place for a while. 

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