I think it is a Couch's Kingbird, but it could be a Tropical Kingbird, as we have both in this area.
The only sure way to tell them apart is by sound.
Feel free to Comment or Critique any of my photo's.
Thanks for looking!
HI CM, I have an app that identifies birds pretty accurately, and your Pic seems to be the tropical king bird. But as you mentioned it is very similar to others except for the song. Anyway hope this helps a little, and nice shot by the way.