Nest building continued today, Thursday 8th March, one week on from first discovering this nest site. I arrived at around 10 this morning and both birds took an equal part, building until just after 1.00. There was nothing different about today, mostly moss and the occasional piece of grass were brought. Moss is gathered from boulders high and dry or sphagnum moss from the dry bank. The male seems to have a preference for sphagnum, the female gathering mostly aquatic moss. At one point the male responded to an alarm call from the adjacent woods, he left the nest and perched on the rocks beneath and then sounded a musical call of warning to his mate and they both departed. I suspected that there was a Sparrowhawk nearby, I looked around but couldn't see it for myself. I undertook a count of visits to the nest for an hour between 1120-1220 both birds between them visited, with nesting material 17 times. A pattern of leaving the nest seems to be developing, as soon as one of the pair arrives, the other bird immediately flops in to the water beneath the nest and then swims down stream to a nearby rock before flying off to gather more material. On some occasions the male would instead, fly upstream returning quite a while later.