Looks like a beautiful Hummer but I think shooting at 2.8 really limited the detail to that pretty patch of blue under the chin, that looks sharp, maybe a deeper dof would bring out more detail in the rest.
What a stunning HB you have shared here with such vibrant colors, and a fun pose. It appears as though the eye of your HB is soft which hurts the image. If you look closely, you will notice that the bird's throat is sharper than the eye. It's important in wildlife and bird photography that if nothing else, the eye be in focus.