Though the numbers of Pied wagtails frequenting Cardiff Bay Barrage can vary considerably, from half a dozen to a couple of dozen depending on the time of year, there are a few permanent residents that have their own little territories. This is one that can often be seen, as here, stepping out along the tops of the concrete walls next to the sluice gates, searching around the mosses and lichens for the myriad of tiny insects that fill its tummy each day.