Are you very sure of your Amazon's age? From what you describe, he could seems to be entering puberty i.e. going into breeding condition and hence the territorial agression. Some Amazons are like that for just a few weeks in a year.

Just leave him alone for a week or two and watch him carefully when approaching his cage to take him out. I think he should settle down. By the way what type of Amazon is it? The 3 "hot-heads" types are Yellow-napes, Double Yellows and Blue-fronts.


Rupert