ear to the ground vs perspicacity

ear to the ground

noun
  • The practice or characteristic of carefully gathering information; a state or mindset of attentiveness. 

  • Pursuing the practice or having the characteristic of carefully gathering information; well-informed. 

perspicacity

noun
  • Acute discernment or understanding; insight. 

  • The human faculty or power to mentally grasp or understand clearly. 

How often have the words ear to the ground and perspicacity occurred in a corpus of books? (source: Google Ngram Viewer )