Giving each other, different species, enough space keeps the peace out there. With a limited number of dry spots to sit, and still be safe, marsh birds have learned to make it work.
Double-crested Cormorant with a Great Blue Heron.
Oh yeah…there are exceptions. Great Egrets and the Great Blue can’t make this work for more than a few minutes. Both fit into the ‘alpha predator’ category. It becomes an issue of territory.