The day I took these shots the Duckweed must have been particularly dense. I’m guessing no wind to push it along the waters surface.
If you look at each of these photographs you will see the Heron, and down below his shadow on top of the swamps surface. I never noticed it until working on the images later.
Duckweed floats and really has no stem or even visible leaves.
It must have been more thick than usual, but did make for a little more interesting shot of the Great Blue fly by.