Today's OED antedating: "to put one’s ear to the ground"

To put one’s ear to the ground, slang, to make oneself well-informed ("ear," n.1, sec 1 (c), first use cited 1920): Book titled Ade’s Fables, by George Ade, 1914, p 185: "Sylvester, after looking at the Signs in the Sky and putting his Ear to the Ground, discovered that he was thoroughly impregnated with the new Progressive Doctrines."