One night last May when my mother was in her final weeks and I was always on alert expecting an emergency call, I was unable to sleep, lying awake at 3AM with anxious thoughts and a runaway imagination. I tried to reason myself into a calm state, but you know how that goes. At 3AM one’s ability to reason is generally fairly weak, and the more I tried to calm myself, the more the mental loops tightened into knots. Gradually a sound from my open window began to penetrate the tangle of my mental gymnastics. Could I be hearing birdsong? A bird singing in the dark? At 3AM? It must…