I've had my quaker for a little more than 2 weeks now, he is about 17-18 weeks old. I've already been to the vet and he has a clean bill of health. My quaker has been having serious mood swings daily. One day he'll be a sweet little bird and the next he'll be a screaming biting monster. I do believe he is going through his first moult. He has a lot of pin feathers and he has been losing a lot of down, and he grooms for most of the day. Could this be accounting for his mood swings?
We also moved his cage from the corner to beside a window (because it was very dark). Could the move have caused his mood swings?
What do i do what he screams? I try to ignore him and tell my whole family to ignore him. And when he bites i try the earthquake method but it seems to just make him bite my fingers much harder and more aggressively. He isn't getting the concept. It usually comes down to holding his mouth closed and saying "NO". and eventually he has to go back on top or inside the cage.
I do put him on my shoulder but only when he's well behaved and today when i was whistling (which i usually do with him) he attacked my face!.
How do i help my quaker with all this bad behaviour? Is it the moult or is he just a spoiled baby and acting out?

I tell my conure "no screaming" in a stern voice while looking in his eyes. It works until he starts screaming again
Not sure if you have "Parrots for Dummies" or not. But there is a section on hormonal changes that birds go through. Tsuke can be the same way too. One day he is the sweetest thing and the next day he is possessed by Satan. One day he is quiet and the next day .......not so much.
And moving cages to other places can cause that. I have a very small place and only have two places for his very LARGE cage. If I move it he can be a butthead for a couple of days. My conure is on a totally different schedule from the other birds......and if that schedule is interrupted in ANY way he turns into a butthead. But he is the most loveable bird I have....second to Cassie my tiel who loves to give kisses and wants scritches all the time.
Good luck.

I forgot to address biting. Don't squirt him with a spray bottle..............
Sternly telling him no biting works with mine. I then put him in the cage and walk away. This allows both of us to cool down. I don't let him out again right away. When he offers kisses or asks for me to sing to him I will then take him out but I don't ignore him for very long as this causes him to scream or cry at me.

Molting can make little monsters out of them, and Quakers are moody anyway! Plus if you've only had him a couple of weeks, he's still adjusting and it could be that sounds or smells or sights in your home startle him because he's not used to them -- things you don't even notice -- and that could make him grumpy. Birds in general are very nervous and easy to startle. My Bonnie was sitting in (not ON, ) her food dish munching away and suddenly she freaked out and flopped to the furthest perch, squawking. A second later she started chirping and singing like nothing had happened. She's a budgie, but I've seen Clyde do similar things.

When you moved his cage, that probably upset him, too. Quakers HATE new things so he's going to be grumpy about that.

As for the biting, he'll probably always bite some. Clyde bites when he doesn't like something, when he's tired of being petted, when he's grumpy, when he's playing ... I rock my hand a little but sometimes that just makes him dig in more so he can hang on. When he bites my ear, I touch his beak and say "no bites, kisses!" and make a kissing sound and that works sometimes and not so much other times. As time has gone by -- we've had Clyde almost six months -- his bites have gotten gentler. He has to be really annoyed to bite hard now. Mostly it's just a nibble, his way of objecting to something. If I don't holler and jump, it stays gentle. If I jump and squeal, he bites harder. If I laugh, he usually laughs, too. Try not to give him a big reaction when he bites.