MYSTERY RAPTOR

On the O'Reilly's Retreat Bird Week, I managed to see this raptor from the balcony of our room. I first thought it was a whistling kite, but I am not so sure now. I do not think it is a square-tailed kite. Could it be a whistling kite with sun shining on its head so much that the camera made the head look white? I don't know. Do you? If you can tell me what this raptor is, please do by commenting on this post.

A photo of the bird 

A cropped version of the above photo