My nanday doesn't seem to realize that he has tailfeathers and when he glides down he seems to break them. Then they fall out...right now he has one left. He's 8 months old. When he matures will he understand that he has tailfeather for a reason??
If your birds wings are clipped - make sure they are not clipped to short. A parrot whose wings are clipped to short can not control their falls. This can cause worse things to happen than broken tail feathers - like a broken beak tip or even broken bones. If this is the case take steps to minimize the falls until the wing feathers can grow out.
Some birds are clumsier than others, but usually birds are very careful with their feathers. If this continues you need to have the bird examined by a vet for underlying causes and to make sure there is not other damage to you bird.