In the distance, I saw two coots. One had fluffy infant down, clearly a chick despite now being grown to adult size. The other was in silhouette. I assumed it was one of the parent birds. Coot adults invest a lot of parental care. They share brooding duties on the unhatched eggs, and both of them carry on feeding their chicks even when the young have grown to full size, and look like they should be able to (and indeed do) get their own food.
I moved somewhat nearer to try to get a better angle to picture them from. As I focussed the camera, the previously silhouetted bird dived. When it surfaced, vegetation in its beak, I could see that it too was a chick. Instead of eating the food itself, it immediately gave it to the other chick, passing it from beak to beak in the way a parent normally would.