Auriculars

Although birds lack external ears, the auricular feathers are precisely structured to funnel sound into the ear canal with minimal aerodynamic drag. In owls, the facial disc forms a parabolic reflector of sound, and the auriculars are underlaid by a moveable skin flap (operculum). The auricular patch often contrasts with surrounding head plumage, forming a key field mark in species such as raptors and shorebirds.