I observed a couple of interesting pieces of behaviour this morning. The female is very quiet in everything she does and when she is the Dipper that I can see in front of me, I am quite certain that it is her by her quiet demeanour. This morning for example I saw her slip out of the nest and then fly up river. After a few minutes a bird returned and I knew immediately it was the male, he flew in calling very loudly as normal and then immediately started singing to proclaim his territory. A minute or two later she arrived back and very quietly started to look for prey, underwater of course. The male sat waiting for her, she flew to him and then they both flew off back up river together. I checked the time that she had been off her eggs, yesterday it was 8 minutes. It was around 8 minutes again when she flew back and very quietly slipped back in to the nest. I need to confirm this with many more observations over the next week or so, but it appears that the birds have an "internal clock" that instinctively dictates their behaviour to a strict timetable. Hence the male visits the female in the nest every 30 or 35 minutes. This morning I watched him fly up to her and make quite a noisy fuss as he communicated with her, hanging on to the nest with the majority of his body mass inside. Previously I had thought he was feeding her but I am 100% certain that he did not carry anything to the nest on this occasion. It's obviously just a way of confirming and strengthening the pair bond.