A stressed bird will reflect its anxiety in both subtle and overt ways. It may cower in a corner of its cage, or it may strike at anyone who comes near. It may engage in self-destructive behavior such as pulling or shredding its feathers. Even worse, if left untreated or corrected, self-destructive behavior can lead to physical disease.
An emotionally stressed bird will act out in ways that are difficult to ignore. It may scream or bounce up and down endlessly. A normally calm, affectionate bird may suddenly bite unexpectedly or strike and bang its beak on whoever comes near. It might even begin to bite viciously. Your job is to find out why and fix the problem.
Body language is a good indicator of avian stress. A bird with a fanned tail and upraised wings might be in a defensive/aggressive posture. Remember, however, that your bird could simply be playing with you; it’s important to know how to read your bird.
Some birds reflect a change of mood in their eyes. Many birds “pin” their eyes when they get excited. The African Grey is a prime example of this behavior—the size of its pupils changes rapidly. When this happens, you need to be on the alert because the bird is frightened, angry or excited. The bird understands the situation from its point of view and is communicating the idea to you. You must then find out what the bird wants you to know. An Amazon Parrot also uses its eyes to indicate its emotional state. When its eyes are light in color and the pupil is dilated, an attack or bite may be imminent.