Hi I have 2 lovebirds 1 peachfaced and 1 blackmasked I got given the as a pair as someone could no longer look after them,they have been OK together but recently the peachfaced keeps nipping at the other 1 and I need help to stop this behaviour

Separate them immediately! It is quite possible the more aggressive one will peck the other one to death. Forget about mating if that was your intent and forget about behavioral therapy too. I had a friend who did not remove one of her love birds into another cage and the more aggressive one pecked the other one to death. She tried to get the more aggressive one to stop it, but in the meantime the other bird was tormented to death. I guess you can call it a love hate relationship. The aggressive love bird ended up dying a little while later which leads me to think a health issue was going on with the aggressive love bird or grieved to death.

Thank you and no I don't want them to mate they've recently started hiding in my hoody could this also be a problem with the peachfaced being territorial.

I've always heard it is the female more likely to be jealous and territorial in any bird species. My son bought a parrot before he married and he was told it was a male. After he married the parrot became jealous of his wife every time she was near him and still is somewhat. Also, one day the parrot laid a couple of small white eggs positive proof she was a female and not a male as told by the experts! The hoody hiding might be a sign of the instinct to nest perhaps.

Oh... by the way, A bird can become very nippy and bite when they are not handled regularly. I now have my son's parrot because of her diving for his wife's head when out of cage. They also have a baby now and have concerns about the parrot hurting the baby. I have put a soft hand towel around her and have held her trying to get her calmed down again. She use to fly around and land on my shoulder, but one day she bit my neck very hard and others too. So I don't trust her, but if I'm singing she joins in and loves to mimic. She laid 6 eggs over a period about 2 weeks ago and has built nests with paper towels. Every spring this happens, the egg laying. Of course they're not fertile and eventually I have to remove them.