While you may think of discipline as scolding or harsh retaliation, parakeets don't see it the same way. A parakeet can't make the logical connection between his misbehavior and your stern reaction. Instead, take a tempered, calm approach to discipline your bird and train him to behave.
Ignore your bird when he misbehaves. When your parakeet shrieks, he is looking for attention, and even negative attention is a reward. Ignoring him until he stops teaches him that acting out is futile. This only works if you are consistent, though, so don't give in to your bird's demands for attention. Only ignore behaviors that are within reason, like yelling. If your bird bites, for example, take a more proactive approach.
Teach your bird through repetition that certain behaviors net undesirable results. More simply, if your bird misbehaves, deliver a negative consequence by removing a privilege. A good example of this is if your bird bites you when you are holding him. When this happens, calmly set him down and wait a few seconds before allowing him to perch on you again. Do this every time he bites, and he will learn that he loses his perching privilege when he bites. Always be gentle and even-tempered while doing this, though, because if you act frustrated or handle your bird roughly, he will only learn to be afraid of you -- which can lead to more biting, not less.
Praise your bird frequently for good behavior and show him plenty of attention. By doing this, a negative response like ignoring your bird goes a lot further. Parakeets learn more from the absence of positive reactions than from the presence of negative ones.
Consider your parakeet's feelings. Not all birds are alike, and behavior we interpret as "bad" may actually be your bird's attempt to send a message. For example, if your bird continues to bite when you hold him, and the setting down method of discipline makes no difference over time, consider that maybe your bird doesn't want to be held, and that setting him down is a reward to him. Similarly, birds rarely misbehave when they have everything they need. If your bird shrieks and acts out in his cage on a regular basis, he may be bored, lonely or not getting enough to eat.
Tom Ryan is a freelance writer, editor and English tutor. He graduated from the University of Pittsburgh with a degree in English writing, and has also worked as an arts and entertainment reporter with "The Pitt News" and a public relations and advertising copywriter with the Carnegie Library of Pittsburgh.