Parrots are usually noisy just after the sun comes up and just before the sun goes down. This is entirely normal and means that your bird is happy, well adjusted and feels secure in your home. Sometimes screaming can happen at other times and might indicate fear or a need of some sort, it’s important to read other body language as well. It can also indicate that your parrot is bored, does it have plenty of toys and is it getting plenty of attention? Screaming can become a behavioural problem when it gets reinforced. If you continually run into the room when your bird screams or shout at it to be quiet may reinforce that behaviour, birds like attention and they don’t distinguish between good and bad attention. The best way to stop your bird screaming is to make sure it has plenty of out of cage time, toys to play with and then to ignore the screaming altogether. Not easy but try to just carry on with whatever you’re doing and don’t interact with the bird at all until it is being quiet. Hopefully the bird will realise that screaming gets it nowhere and will stop screaming.