Just three minutes separates the latest picture in the previous set from the earliest one here. In that time, the shelduck parents had rounded up their dispersed ducklings into a tight group. They had led them to the lower end of a narrow stone jetty, and were shepherding them into a tight group just above the high tide mark.
It became clear over the next few days that this was a regular overnight resting spot, with the ducklings sleeping in a huddle while the parents were protectively nearby.