Fantastic!
Frankly, you keep posting photos of these birds the likes of which I have never seen anywhere else. Your study of them appears to be unique, ... without equal.
I love that you are unhappy with these, as it means you are setting the bar higher, and we can look forward to more! What you've done thus far, your "recipe" to get these shots, is clearly a winner, but yes, I can imagine from behind the lens that you could strive for more. I saw the same look in the eye of Tiger Woods the first year he won the Masters. 
To some point, luck will play a part, you've done what you can, you are in the right place with the right skills and a good eye. I bet you get better, and I bet luck provides you one day with the shot you are looking for.
