I love it when Herons and egrets do this. In another shot of the series, the bird does this while looking at the camera. Strange to see into their mouths like that. I thought the profile was a nicer shot.
This is a superb image (as are your others), tack sharp and perfect DOF. Am surprised it hasn't received more comments. Lovely bird too, we only have access to Grey Herons here in the UK (I think they're called Great Blue Herons in the States). Voted.