This image is a great action shot of an unusual sort. Herons do not often allow photographers to get very close to them. They also tend to prefer calmer water for their fishing. The unusualness of the image subject helps to capture attention immediately. The bird's head is positioned near a vertical line using the rule of thirds while still giving room for the action to occur on either side of the bird so that we get a full appreciation of the situation. The motion is captured at a moment of impact and leaves the viewer feeling that the action will continue any moment.