Neat behavior and I like the shallow DOF. I think a lower, more side-on perspective would've helped this image though. As is, the lack of separation between the head and the body causes some confusion. The boxy crop was the right choice IMO. You might want to turn the blues down in the shadows. Nice attempt, Dan.
I like the idea behind this image.
It is a great textbook shot showing the "shoveling".
I see some blues in the shadows (which is normal) but I would agree with Aditya and tone the blues down.
This is the kind of shot that would work better with a wide angle lens to get a lot more DOF. No lens could get the entire bird in focus with this angle but you certainly would get more separation between face and body,
Gail