While sometimes a screaming problem starts because of boredom, loneliness, or frustrated mating desires, it is very common that screaming develops because an owner has inadvertently reinforced the behavior by rewarding screaming with attention. The problem doesn't develop overnight and there are no magic cures but good discipline and careful alteration of the owner's behavior patterns can often solve it over time.
Some parrots fear nothing — even the tiniest birds challenge huge rivals over territory. Other birds fear almost anything — falling or flapping in panic if a shadow crosses the ceiling.
Although bird poop has no odor, and is relatively harmless, few people are willing to venture into public with it on their shoulder for friends to notice and say "Hey, I'll bet you have a pet bird". True bird lovers understand that occasionally one will be pooped on by their loving pet and they accept it with grace and dignity. I am one of those people.
When a bird is getting ready to relieve himself, he’ll squat just slightly and flick his tail in an upward motion. Observe him in his cage so you can begin to recognize the movement he makes when getting ready to “go.”
Bird's Screaming, what to do?
Fearful Parrot
How to Potty Train Birds
Train Your Parrot