descry vs pick up on

descry

verb
  • To see, especially from afar; to discover (a distant or obscure object) by the eye; to espy; to discern or detect. 

  • To announce a discovery: to disclose; to reveal. 

pick up on

verb
  • To notice, observe, learn, or understand, especially something otherwise overlooked. 

  • To adopt a practice in which others already engage. 

  • To continue or build upon (for example, a task, analysis, or narrative), beginning from a point at which someone has previously stopped. 

How often have the words descry and pick up on occurred in a corpus of books? (source: Google Ngram Viewer )