Nymphicus hollandicus (Cockatiel) is a species of birds in the family cockatoos. They are found in australasia. Individuals can grow to 40 cm. Reproduction is dioecious. They rely on flight to move around.
Definition: the air-filled cavity within the skull of vertebrates that lies between the outer ear and the inner ear. It is linked to the pharynx (and therefore to outside air) via the Eustachian tube and in mammals contains the three ear ossicles, which transmit auditory vibrations from the outer ear (via the tympanum) to the inner ear