F/11.0, 1/500, ISO  320.

Laughing Gull

Why is a river rich?

It has banks on both sides.

Interesting Fact:  The adult Laughing Gull removes the eggshells from the nest after the eggs hatch. If the shells are not removed, a piece can become lodged on top of the slightly smaller unhatched third egg and prevent it from hatching. ( https://www.allaboutbirds.org/guide/Laughing_Gull/lifehistory )