The avian ear conforms to the general terrestrial vertebrate plan, being divisible into outer, middle and inner parts. The outer ear is generally a simple and short feather-covered (earcoverts) tube (the meatus), leading from the exterior to the eardrum which is situated just behind the angle of the jaw. In some birds the covering of the ear is lacking, thus having an exposed external opening. In owls the meatus is enlarged and more complex than in other birds. The sound (-energy) is transmitted from the eardrum, through the air-filled cavity of the middle ear, to the inner ear and especially to the cochlea which is the auditory part of it (other parts are involved in keeping track of body-orientation and -movements) and is the real receptive part. Birds have a smaller auditory spectrum (one or two octaves at each end), but a quicker rate of response, as compared with mammals. Other auditory functions (e.g., pitch discrimination, absolute sensitivity) are probably similar.
Alternative form for ear : ears.