To hear the sound of a bird's song it is necessary that we be corporeally conscious in the entirety of all the other sounds and the silence that makes hearing it possible. An ambient consciousness in the aural whole is, therefore, of necessity, to hear a particular sound.
It is often difficult for us to gain the insight (Skt. vipashyana/Pali vipassana) necessary to observe the functioning of the "subtle" (feeling) body, memory (smrti/sati), and craving (trsna).