<human>: Summarize the given text in a few sentences.

I'll try to keep this short. 

My mum was given an Indian Ringneck(ed?) parrot about a year ago and all was well until a few months ago. She's a bird lover so she treated it well but eventually it turned on her. It attacks her, bites her (enough to draw blood) and she struggles to get it back in the cage after she's let it fly around. 
It got to the point where she was going outside to escape it so it had to go. Since my sister can't take it, I've now got it.

Don't get me wrong - it's an awesome bird and I've always liked parrots. It also likes me (at least a little) since my sister and I are the only people allowed to stroke it without being bitten. I just have no idea what to do. Mum gave me the cage, more food and treats than a small country eats in a week and a car full of toys. So now it's sitting in its cage in my study (where I spend most of my time) and it seems to be fine. It's clicking, 'tweeting', climbing around, staring at me and, now, sleeping. 

My question is: what do I watch for and what do I avoid doing? What do parrots like? What do they hate? Can you tell whether they're happy or sad? If it DOES bite, is there a way to train it out of that habit?
<bot>: mum's parrot became too aggressive, I now have it. I have no idea how to treat it since it only has two legs and doesn't bark.