Whenever I come to the edge of a marsh, the first open area, I try ‘sneak’ in. Basically walk slow, no noise, blend in with any background. Stepping out into the open from woods gives any animals the advantage. They will spot you first, every time.
Of course that means there is something there to see you. Certainly not always true.
However as I stepped out a Green Heron jumped up on an overhang, ready to exit if needed.
Not far down the marsh Great Blue Herons were suddenly watching me too.
So my skulking along worked. I was able to get the shots before the fled.
OK, they actually went nowhere. I took the shots and they went about their business. I moved on first. But it’s still a good idea.