From Everyday Zen by C. J. Beck:
It's not that "I" hears the birds, it's just hearing the birds. Let yourself be seeing, hearing, thinking. That is what sitting is. It is the false "I" that interrupts the wonder with the constant desire to think about "I." And all the while the wonder is occurring: the birds sing, the cars go by, the body sensations continue, the heart is beating—life is a second-by-second miracle, but dreaming our I-dreams we miss it. So let's just sit with what may seem like confusion. Just feel it, be it, appreciate it. Then we may more often see through the false dream which obscures our life. And then, what is there?
1-Minute Contemplation: Take a minute to close your eyes, and just listen. Listen to the first layer of sounds around you, the sound of your breathing, cars, typing, air conditioning. Then sink deeper and listen to the second layer of sounds, perhaps birds in the background or a deeper electrical hum. Then sink deeper and listen for the third layer—maybe you can even hear your heart beating. Then open your eyes, and maintain that deeper awareness as you continue about your day.