The sound was unmistakable and led me outdoors to face the thick woods across the road. In the advancing twilight the sound pierced the darkness again, and then again. The ghostly mournful wail, best ...

Part 1. 'I don't do calls' -- Crossing the sound barrier -- Tone and timpre -- Pitch and frequency -- Rhythm and timing -- Part 2. Put it all together and what have you got? -- Simple calls -- Simple ...