Hi,
It’s possible that he is experiencing hormones for the first time. This is a common cause for a personality change. This is temporary, but will happen anytime the bird is hormonal. Otherwise, you need to think of anything you may have changed or done to cause him not to trust you. Did you get another pet, were you too busy and not handling him as much, did you scold him for something, did you change something in the environment – things like this can have an effect on a bird. I’ll give you the links to our behavior & training pages to help you better understand his behavior and how to work with him. This is the type thing that might require the help of a behavior consultant.
Pet Bird and Parrot Behavior
Teaching Your Bird
Thank you for asking Lafeber,
Brenda