I was sitting in the hide overlooking Holton Fen at dusk (4 47 pm) when a Bittern flew across the water near the wood to my right, then dissappearing over the phramites reed bed. It has been spotted a couple of times recently, initially by Dave Blackledge.
According to Collins Bird Guide, they will only breedi in extensive phragmites reedbeds, of which there is a large one on Holton Fen - previously planted by the Thursday workparty many years ago. Perhaps it was looking at its potential!
Unfortunately, although I did have my camera with me, the light was poor at that time of the day and it was distant. These are only a record shots..