Stop rehearsing the bite
If the bird bites every time you ask for the same thing, the setup is too hard. Use more distance, a perch, a target, a smaller reward step, or a shorter session.
Hands should not rush the bird
Fast hands, fingers near the face, reaching over the head, or grabbing from inside the cage can push a nervous bird into biting. Slow down and let the bird approach the hand instead.
Cage bites need a different plan
A cage can feel like the bird's safe place. Do not reach in and argue with the bird. Teach stationing, offer a perch at the door, and clean or change bowls when the bird is calmly elsewhere.
Watch overexcitement
Some birds nip when play gets too wild, when they are on a shoulder too long, or when favorite-person energy gets intense. Step down, pause, and reward calm behavior before the bird tips over the edge.
Do not punish the bite
Yelling, flicking, shaking, or forcing another step-up usually makes trust worse. After a bite, get safe, stay boring, and change the plan so the bird does not need that answer next time.