I did ask the Head Keeper on Friday and he agrees that the other parent is a Wigeon. He added that there is another hybrid that looks almost 100% Chestnut-breasted Teal but isn't, plus there are two further Chetsnut-breasted x Wigeon hybrids, one of each sex (I cannot have been too observant where these are concerned). I have spent some of Friday, Saturday and Sunday afternoons trying to photograph the relevant birds (not very successfully on Saturday).
