What changes the behavior answer
Stop the interaction calmly and look at what happened before the bite: hands entering the cage, forced step-up, touching, toys, food, another person, or a warning you missed.
Respect earlier warnings
Leaning away, pinning eyes, lunging, open beak, tight feathers, raised crest, hissing, or moving away may all mean back off before the bite.
Change the request
Use a perch, station, target, treat, or open door instead of pushing a hand into the bird's space. Reward choice and small steps.
Check pain and hormones
Sudden biting, cage guarding, nesting behavior, feather changes, appetite changes, or handling sensitivity may need health or hormone review.
Better goal
Teach the bird that clear body language works, so biting is not the only way to be heard.