My budgie Sheik is about 5 months old. Nowadays he flies around my home from room to room. When he perches on one place I've noticed that he suddenly lifts one wing and starts chirping at it like he does when he is angry with something. He may even give it a little bite.
At first I thought his muscles were getting used to his flying so much but it has
been more then a month since he started flying.
What might it be?