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The bird was placed inside a sound-proof chamber in a cage separated in three distinctive zones (zone 1 near the loudspeaker, zone 2 with a cup filled with millet, and zone 3 the furthest from the loudspeaker). The entrance of the sound-proof chamber was on the left via a two-way casement window. A webcam and a loudspeaker were positioned near the cage and a microphone recorded the subject’s calls.
