The bird in question was found in august sitting on our lawn and chirping in a rather bad condition. He had one eye closed, loads of feathers missing and he had a broken foot as well:
I took out a bowl of various seeds in order to lure him, and after jumping up to a branch he accepted the offering and settled down inside it as I took it indoors and put him along with the food bowl in an impromptu cage till we could find a better cage, and later take him to an avian vet. We had later on checked with several vets if anyone had lost a lovebird, but wherever he was from he had no owners searching for him. As to how he ended up in that condition, he must have escaped and gotten attacked by a predator and for a very long time he was very, very frightened and shy.
Fast forward till now:
and he's a beautiful and very healthy and active lovebird. He has a big cage with plenty of toys he play with, and try to get him new ones so he won't be bored. We have put him in the living room and he doesn't show any signs of shyness anymore and eats when I eat, ask for baths but do one objectionable thing - he bites till he draw blood, repeatedly.
He was shy for a long time when I put my hands in the cage to clean up, refill this bowls etc.
But nowadays he doesn't really mind, and sits on my hand sometimes if I have seeds in it and eat from it and even lets me pet him. But sometimes during feeding he becomes very vicious, and attack my hand and bites really hard - its not playful nibble or an attempt to hold onto my hand.
It's very painful.
And I try to tell him no in a not too loud voice, slowly moving my hand away so as not to frighten him. It's almost like he think I will take away his food when I do this, so his response is just to bite on harder and try to tear my flesh.
But it's not just during feeding that he shows this behavior, sometimes he and I are just playing or bathing with my fingers lightly splashing the water (he refuses to bath otherwise).
I have read advice like firmly holding the birds beak, or rapidly lowering the hand, but I am afraid that he will completely lose the trust he has slowly built up towards me, and revert back to how he was when we found him wild.
Would be very grateful for any sort of help or advice I can get.