When I checked the nest yesterday there was still no chicks in the nest which wasn't a surprise as they were not really expected until 11th or 12th of April. So I was quite hopeful when I visited to check this evening.
Thankfully the water level hadn't risen any further, infact it had brobably gone down an inch or two. I waited for the female to leave the nest before moving down to check the nest. I am really glad to be able to report that 3 of the eggs have hatched and three healthy chicks are in the nest. One egg is either infertile, or "dead-in-shell" or more likely incubation started with the 3rd egg and not the 4th. If this is the case this will contradict everything that I have read previously which seemed to suggest that incubation always commenced when the clutch was complete. If the 4th egg should hatch tomorrow, then this will confirm that incubation started on Sunday, when there was only 3 eggs in the nest. I am looking forward to finding the answer tomorrow. The chicks were pink skinned which was a surprise, I expected them to be dark.

I watched the male already working hard finding food and delivering it to the nest, even if I had not checked for myself, I would have known that there were chicks in the nest just by the male's change in behaviour.