Amazon getting increasingly more aggressive over time

[Muffinburgler]

Hello, I visit this forum a lot as a silent stalker but decided to finally make an account to ask for help.

I have a male amazon named PD who's been getting nastier over time. I've had him for four years. I adopted him when he was 11. He was never very affectionate, but he wasn't nasty either. He'd have his usual hormonal fits and then calm down, but lately he's just nasty, constantly.

I can't go near his cage anymore, he'll lunge at me through the bars. He tries to get my fingers when I feed him. Obviously that makes it hard when it's time to let him out of his cage for play time on his play tree!

He used to eat food from my hand, but now if my hand is within a 2 foot range he makes it his mission to break my bones. He's also gone for my mother, landing on her head and going for her scalp and neck. I'm at a loss of what's causing this aggression! Nothing in his life has changed other than his diet (I'm trying to get him to eat healthy but he is not having it.)

I've tried positive reinforcement, where once he stops biting he can come out of his cage to play. But then he just saves the biting for once he's out of the cage! It's making it very hard to love him.

Naturally he's a perfect angel when he's at the vet, so she doesn't quiet believe me . . .

[Wolf]

Well I believe you and I haven't even met your bird. Of course he is on his best behavior while he is at the vets, he is in an unfamiliar environment and that means that it is potentially dangerous to him and since he knows you, suddenly you are his best friend. This is quite a common as well as normal behavior.
What is his current diet? I am glad that you are trying to make it more healthy for him, what are you doing to make his diet healthier? What prompted this change after 4 years?
What time does he get up and go to sleep? how much out of cage time does he get on a daily basis? How much and what kind of interaction do you have with him? Is he clipped or not?
I think that your problem is that your amazon is hormonal and has been fed a high protein diet and has been kept at a human light schedule for at least four years and quite possibly longer and if I am correct this bird is in constant pain which is causing all of the aggression that you are experiencing. The answer to this problem is to put him on a strict solar light schedule which is the same as the wild birds outside your window receives. It means that if you cover his cage at night, then you will need to uncover him before it starts getting light outside so that he is exposed to the twilight period of dawn and that you need to also expose him to the twilight period of dusk in the evening and go to sleep by full dark. This light schedule accompanied by a low protein diet will fix this problem, although I can't say how long it will take to correct the issue. It depend on how far out of sync his biological clock is. This is the clock that controls the breeding cycle in the bird. Unfortunately if this is the problem then this is also the only cure for the problem.

[Pajarita]

Welcome to the forum! I love amazons (have 6 myself) so, yes, please, give us details as to his light schedule, diet, flight, out-of-cage and one-on-one time because, usually (and I am talking 99% of the time!) it's hormones that makes them so aggressive for no apparent good reason.