On the petting one second then bite the next, my green cheek this us a way of life lol I don't get bit ( very rarely) because I'm watching and we have had 7 or 8 years of practice. She does not like a hand to come towards her from the top. Like are you trying to kill me here?
On my quakers, they seem to be beak bullies. Testing...Testing ...can I get away with this. Mine do not bite hard, we have bite pressure down ( except at cage) but they grab, push, scrape, hold, bash, nibble, nip, do a lot of beak communication. If they are trying to beak scold or beak boss me , I make eye contact and tell them " be nice" if beak pressure is exceeded/exceeding I tell them " be careful "
I've found with my quakers ( never in a million years my green cheek) I can push beak away with finger or scrape them off gently with a finger from whatever part of me they are biting and tell them no that's not nice. We look at each other, and they are like ok, respect, i'll stop ( for now hee hee) or after a bite I have them step up and eye contact telling them no that's not nice. I think they really want to bully but are ok with you calling them out on that.
I read this great article of wild quaker flock dynamics ( I will try and find) the quaker were observed in loudly ( ofcourse) engaging in mini fight clubs, no injuries, more as for fun. Observed as not to determine dominance, more as rough housing. Parrots wouldn't hold hard feelings with sparing partners and would continue to hang out with feed with ect. Tail pulling pranks also done to mixed species in the flock. Mine love to prank by tail pulls on each other and the budgies. My green cheek will not tolerate this and goes ape $#!+ so they leave her alone. Ohhh I hope I can find the video !
Ok not t the one I was trying to find, but a good example of how much they love to squawk, and if yiu watch can see some skirmishes