Nice look-back pose with good sharpness where it counts. Yellows have lots of detail. The perch could be better. I would have stopped down to f/8 and 1/1000 to get more of the bird in focus. I don't mind shallow DOF when the bird's body is facing the viewer because the head and breast are in focus and the OOF parts of the body are behind the bird. With this pose the OOF body parts are in front of the bird and tend to draw the eye. Also, you seem to have darkened the sky and there are some areas around the bird's feathers that reveal the original sky.