How to stop gray parrot from biting?

Question

So it is a very special case here. My mother bought a 1.5 month old gray parrot. He was an adorable and very calm bird.

At the age of 5 months my brother started playing with him aggressively by distracting him, poking him with things, putting fingers in his cage and then pulling them out when the bird started attacking, etc. The parrot started to bite my hand every time I approached him, not "escaping only" bites and very hard. Now that my brother has stopped irritating the parrot, I want to stop this biting issue.

Current situation - the parrot doesn't fear me, and while outside of the cage he will sit on my shoulder most of the time. If I leave the room then he will fly to me if he wasn't already on my shoulder. But my hand approaching him will provoke an attack--he will violently bite it and at times even inflict a bleeding wound--and when I take my hand away from him he will instantly chase my hand to continue biting; after he's done he will usually return to my shoulder.

It's hard to feed him from my hand but it's possible. It is nearly impossible to make him sit on a hand, except when he is taken out of a cage. It is also hard to train him.

My guess is that he bites everything that he doesn't like.

How can I prevent this behavior?

Additional information:

• Current age: 7 months old.
• Parrot name: Kelvin.
• Origin: bought from a breeder, without full feathering, hand-feed by me using a syringe until the age of 6 months old, then he started to refuse hand-feeding.

Answer 1

Well, things turned out to be that being friendly with the bird and loving him, no matter what, worked! Now I have a very lovely parrot. So rules I followed are:

• If parrot behaves bad then do not interact with him for a while (~20 min) (parrots love social interaction and become very upset without it)
• If parrot behaves good then interact with him socially (positive reinforcement)
• Do not punish your bird physically
• Do not punish your bird by depriving food
• Do not scream at your parrot (parrots don't understand that)
• Love your bird, even if he bites :)

Things that didn't work:

• Positive reinforcement by means of treats (still don't know why)

That is only what I learned about my parrot, your case might be different and some things need to be adjusted to your parrot.

Answer 2

Judging from the behavior of our 2 African Grey parrots (25 and 15 years old) they can be somewhat unpredictable. Because yours has been teased, I think you have 2 strikes against yourself. Ours have never been teased and still will pinch on rare occasion. There is a positive affect of approaching the bird with confidence; my adult son visits every couple months, walks over and picks up one bird; he has never been bitten.

Regarding that same bird, I am careful to keep my fingers away from his beak (he will not bite an arm or the back of the hand). An acquaintance of ours has a rescue for parrots, macaws, etc. and some have behavior problems; she can walk over and pick up any one of 20 birds. I don't know her secret, but it must be partly self-confidence.