I have a male severe macaw named Buddy. I don't know how old he is, I don't know anything about his past, and I don't know what he has been through. He doesn't have a leg band and all I know is that he's a rescue. He can step-up and sit on my shoulder without any issues and he has times when he's a good bird but he is aggressive towards anyone else and anything else. I want to be able to pet him and hold him without worry but he'll try to bite if you do. He usually lunges out at people except me and often screams for hours, even if we ignore him. I've tried teaching him tricks such as target but he just attacks the stick and breaks it. I've heard severe macaws are more on the wild side and tend to be more nippy than other parrots but he's almost impossible to work with and I just need some advice. Thank you.