When the Herons leave the open marshes for the swamps and rookeries it becomes a little easier to get close and in flight photographs.
However now there are new challenges. The first being all the trees and branches. A quick shot can be needed before tree limbs ruin an image.
The second issue comes in a month or so. Things turn green and leaf out. Again blocking our view.
But really, this is wildlife and to be expected. If I wanted the perfect shot I could get a parakeet.