My guys don't scream very often but if one of them does do any loud shrieking for more time than I like, I tell him to "knock if off" and just ramble on for a little. If that does not work I sing. Luckily my parrots like to listen to me more than themselves. If that doesn't work, then turn on the radio/stereo and cover the noise up. Darkening the room is also something that might work.