Noun
(idiomatic) The practice or characteristic of carefully gathering information; a state or mindset of attentiveness.
(attributively, usually hyphenated) Pursuing the practice or having the characteristic of carefully gathering information; well-informed.
Source: en.wiktionary.orgEvery politician must be able to keep both feet on the fence with his ear to the ground. Gracie Allen
It is hard to look up to a leader who keeps his ear to the ground. James H. Boren
I used to live in New York, and I have friends that work in the fashion world, and I feel like I had an ear to the ground there. Gillian Jacobs
It's tough trying to keep your feet on the ground, your head above the clouds, your nose to the grindstone, your shoulder to the wheel, your finger on the pulse, your eye on the ball and your ear to the ground. Traditional Proverb
Open up and don’t resign yourself to the couch and the pot of tea and the digestive biscuits and Ear to the Ground. Source: Internet