I have no idea what this is, perhaps my learned friend Pamela will know. I took the photo this afternoon on Llangorse Lake near Brecon. I wasn't very happy with the photos I took but I did like this one.
@susiemc Sorry its taken so long to get it. Its a male Mandarin duck in eclipse plumage - (particularly male ducks moult their bright flight feathers late summer to be replaced by dowdy ones - hence you think the males have disappeared - by October they return to their full glory)