Bittern on a shed in Thame!

I was on my way to a meeting when I received a call from a chap who claimed to have a Bittern on his garden shed in the middle of Thame. Intrigued as to what it could be and as it was only 15 minutes out of my way, I made a detour. I arrived to find a Bittern on his garden shed! Presumably having been a little disorientated by the fog it seemed quite happy and fit. The chap had bought some mackerel in case it was hungry but before he had the chance to offer it some, the bird flew off strongly towards the town centre. The pic above was taken through his kitchen window.