Their somewhat shrill voices may strike some people as unpleasant, but a Contented bird resorts to its voice only occasionally to emit a warning or an alarm and is more likely to use it for whistling, imitating noises, or mimicking some words it hears a lot.
Young cockatiels can become very tame and trusting.
They grow into lovable companions that quickly overcome their initial, often panicky fearfulness and form deep attachments to the people they know well. Although cockatiels like to be active, their play is not as amusing as, say, that of a parakeet. A cockatiel is quite content if it has something to work on with its beak, branches to gnaw on, or a piece of cardboard or other object to reduce to shreds. Naturally, a cage for a cockatiel takes up more room than one for a parakeet. A Cockatiel also needs considerably more space for flying than its smaller, much more agile relative.