An Indonesian lady was making the sound "Piririririririri" to call her family members in the purple field.
I've never heard such call before but the sound was clear enough to reach the target, I think.
Other than the plants of lavender, such barley crops were fully flourished beside the purple fields.
The rainbow-like stripe was made of such plants with the colors. We headed to the hillside of Mt. Tokachi(dake) after walking around the stripe.