There are a couple of things you can do here. The easiest is keep your cockatiel in the cage when you have visitors over. Your visitors are undermining your bird’s training. And letting him sit on shoulders is a liability to you. He could end up biting someone on the face or their ear or eye. While a cockatiel has a small beak, they have one of the most vicious bites of pet birds – often worse than the large parrots. A cockatiel tends to draw blood, and they tend to chew once they have hold of someone. The larger parrots are much more likely to just cause a bruise, and possible a puncture wound. Cockatiels tend to remove a piece of skin, and can cause permanent scars. You definitely don’t want someone to get hurt, or to pursue legal action against you. Since you are the companion for your bird, there is no need to let others handle him if they are just visiting. This is causing some confusion as well as acting out by him.
Another solution would be to stick train him. This way you can make him step up on a stick rather than your hand. I’ll give you the link with information on stick training.
As far as any type of discipline or punishment – this only causes a bird to lose trust in you. Each time you scare him, he has a reason not to trust you as much. If this continues, you can be facing worse behavior issues as time goes on.
Teaching Your Bird
Thank you for asking Lafeber,