She has probably been taught to scream by the sounds of it, green cheeks are generally pretty quiet with occassional loud moments rather than loud all the time. Ignore her when she screams and pay attention when she is quiet. If you are out of the room dont go back in until she is quiet.
Thanks! But i bought her in March, and she was only about 6 or 7 months then, so she is still an infant, so I cant blame her. All of my friends that come over say that she is EXTREMELY loud, but i'm used to it...
If you bought her in March and she was seven months old then, that means she's about a year old now. She's still a very young bird, but Green Cheeks actually reach sexual maturity when they're 1-3 years old. So, while she may be your baby, she's not an infant