I have 7 weeks old budgie, which is hand fed and he has no fear of me at all. He even sleeps in my hand, getting there by himself/herself /I am still not quite sure of gender/.
He does not bite at all, normally. Not hands. But, it happened twice so far, when I started to talk to him, when he was sitting on my shoulder or on my finger, he suddenly bit me really hard.
I do not understand it. He cannot be in fear, as he can easily just fly away. I do not force him to sit where he sits, I do not even have my lips too close to him, so I do not know what is going on.
It might be the talking or the face itself, I do not know. I do not kiss him.
The situation today was - I sat in front of the computer, he jumped at my keyboard, my hand on the mouse etc., the he flew on my shoulder, I continued working at PC, the I turned my head a little and started talking. He even got closer. I talked and the he suddenly bit me for - from my point of view - no reason at all.
Of course I did not react too much, or at least I tried, but I was surpriced and it hurt a lot, as he hang on my lip, so I might have done some sudden move though. But after that I did not punish him. He flew back to my shoulder and after awhile I put him into cage, as it was already dark and time to sleep.
He is outside his cage most of the day, 4-6 hours minimum, I work from home.
I tried to talk to him while he was in cage, he was close to me, listening for a few moments and then he "attacked" the wires. But when I put my finger inside to scratch him, he is ok with it.
What should I do? Talking to him from distance? Talking to him while he is at cage? Not talking to him? It is clear, that if I try it again the same way, he will bite.

Talk to him from a distance and if he moves toward your mouth, try distracting him with a toy.

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