Ultimately both of our birds came to us as multiple-rehome “mean birds”, and while birds with serious hormonal imbalances or behavior problems most certainly exist (and any time untoward behavior is being exhibited repeatedly, a vet visit to rule things like that out is in order), sometimes it’s simply that the humans are not respecting their space and their dignity for lack of a better word. They’re really smart, and if you don’t respect their boundaries and instead try to make them comport to your standards, you’re going to have an awful time. This can be as simple as expecting them to want to let you pet or handle them really. You are not the one in control here - the bird is. I’d say 100% of the bird bites I’ve gotten were from human error, haha.
I think reframing a situation is the most useful tool we have. Instead of thinking, “that mean a*****e bird just bit me!” think, “I am a 100+lb over 4 foot tall primate and I keep sticking my giant bird-sized hands and arms in this little Einstein-chicken’s face!” The birds never asked to live with us, after all. We brought them into our homes. Our parrot can’t hop in the car and drive to the bird store and buy himself food or new toys or whatever he needs for enrichment; he’s kinda stuck with us.
The other thing is, the only thing we can control in any situation is our own behavior. The bird is an independent variable and they’re going to do whatever they’re going to do - but we can control how we react and what we do, and we can observe what effect that has on the bird and our relationship with them.
I would love for example if Sammy were as calm and sweet as Kirby is, but that’s not the kind of bird she is. When I let go of that expectation and instead alter my behavior so that we have less opportunities to have a bad interaction, everyone has a better time.