Cute cockatiel. I'm sure, if this is your bird, you have a more interesting background/environment to photograph him in. One of the great things about nature photography, even captive nature, is to see the animal in an environment. This image doesn't give me that and I think that is its greatest flaw. Put him on a swing or a fake tree he can peak out of - it would do him justice. I have an african grey - birds are wonderful pets! Good luck in the challenge!
Your bird seems fuzzy; I can't tell whether this is because of the focus, the light or the processing. The shadow behind the bird's head is distracting, and could have been eliminated by repositioning your light source relative to the camera. A stronger catchlight in the bird's eye and more light on his tail would have also improved the image. Since the bird's body is rather drab, placing him against a background which complements the color of the feathers on his head would have made this more visually appealing.
Good composition and a nice tight frame. The lighting seems to be a little harsh and there is a bit of noise in the image. The colors came out very well and true to life!