I have had my cockatiel for about a year now. He has always been so sweet and affectionate. He would let me pet him behind the head and he would never bite. I even taught him how to make kissing sounds and whenever I was around he would give me kisses. But now I dont know what is wrong with him. He trys to bite me every time I want to get him out of his cage. He doesn't want anything to do with me. Some mornings I have woke up and his wings will be really bloody. I think its because he flaps them and hits then on the cage. Or because he is falling off his perch.I dont know how to make him stop. What is wrong with him? And how do I keep him from hurting himself?