I'm walking to the ATM at lunch today when I start hearing a faint sound like morning doves cooing. It's intermittent and soft, but still it stands out from the noise of the street. I look up, searching for eaves or some nearby perch. Finding none, I gaze around at eye level. Still the sound, but still no source. Finally, I walk on, gazing down at the ground and see a man sweeping trash into a hanging bucket at the end of a short pole. He is dragging it along the sidewalk and the hollow, intermittent sound it makes is what I took to be the doves.