
Sorry about the long post, I tried to keep it as short and dry as I could. Please bear with me.
Mr Darcy is a rescue bird, his paperwork got lost so nobody knows anything about his past or his age.
The charity I work with is great with big birds, not so much with tiels, so he was fostered in various random places usually packed with bigger parrots.
For one of those weird chances he was fostered in the same home with Keith for a few weeks, and became obsessed with him. With Keith gone, he became obsessed with one of the bigger parrots.
Then he came here, and for a while he was overjoyed with all the tielness, and the sweetest boy you can imagine.
Then, after about a week, he became obsessed with Bubu. Followed him everywhere, sang to him, he was his slave basically.
At the beginning I thought it was cute, then Bubu started to get annoyed, chasing him away, and I became Darcy's enemy.
Bubu is strongly bonded with me (and I likewise), so every time Bubu was with me Darcy would get angry and attack me. He still does that, now I have a few techniques to avoid the actual bite but his behaviour remains very aggressive.
If I move it's worse. If I sit on a chair, with Bubu sitting on my shoulder, he sits near and won't attack. Will just make those little angry squeaks, short, dry, I don't know how to explain them but all my birds do that if they are angry or nervous. Tonight actually he was calm and grinding his beak while perching nearby.

I opened a thread a while ago on TC but apart from the hormone reduction suggestion made once, it was pretty much a monologue, After a while I got bored to talk to myself and abandoned the thread.
I know there is a hormone problem, at least I think there is, but I am afraid this goes beyond something that can be solved with long nights. I used all the hormone reducing techniques and not one of my tiels is hormonal right now.
I was thinking of contacting a parrot behaviourist, but I can't pay their fees and even if I could I don't know any.
With him being a rescue bird, maybe I could find someone willing to give me some sessions for free, this is my hope.
I took Bubu away for a few days, to see if things improved.
They did, he was a much more relaxed bird, not chasing me or anyone else.
As soon as Bubu came back, Darcy got back to his crazy ways.
Sometimes I put Bubu in another room and when I do that Darcy is the sweetest boy you can imagine. He makes me give him scritches, and talk to him. He even sings to me.
When I put them to bed, Bubu goes first. I cover him, and like magic I am able to pick Darcy up, and cuddle him a little bit before putting him to bed.
I am baffled and so frustrated, I genuinely love him and want to help him!
My charity's coordinator is aware of the problem, and we had a discussion because he says that when the weather gets warmer Darcy will go to an aviary. I am against it, as I think he would be great as a pet in a house where he's the only bird around. That, or he stays here and I will have to put up with his ways.
My partner hates him with a passion because Darcy bit him too, and hard

so if he doesn't change, I might have a "divorce" coming up.
Thinking of him in an aviary is unbearable, he likes to sing, interact, he is definitely not a feral bird. Who knows what happened to him to make him such a dr Jekyll/mr Hyde type.
Or maybe I am being selfish and an aviary is a good idea.
What are your thoughts?
Whatever comes to your mind, please tell me. I don't know what to do anymore.
I even thought: what if he actually loves me and doesn't want me to be around Bubu? That would be a problem without solution.
