A cockatiel's crest is one of the clearest mood indicators: a crest held upright and alert usually signals curiosity or excitement, while a flattened crest pinned close to the head can mean fear or aggression, especially paired with hissing or lunging. A relaxed, slightly raised crest during quiet moments generally shows contentment.
Cockatiels also blush โ their cheek patches can visibly darken or brighten when they're excited or engaged, similar to how a person's face might flush. Beak grinding, a soft grating sound made before sleep, is a sign of relaxation and contentment, not distress.
Tail wagging or fanning, different from a dog's wag, often shows happiness or an attempt to get attention. Growly or hissing sounds paired with an open beak and lunging body language are clear warnings to back off and give space, usually related to territorial feelings around the cage or a favorite person.