Fig 2. Schematic representation of the playback sequence.

Three distinctive phases are represented: the 10 minutes silent phase before the playback stimulus (“Before” in white), the three 30 seconds repetitions of the playback stimulus (“During” in black) and the 5 minutes silent phases following each playback stimulus (“After” in grey). The arrows show the exact parts kept for analysis: the last 30 seconds of the “Before” phase, each repetition of 30 seconds of each stimulus in the “During” phase and the first 30 seconds of each “After” phase.