White-headed Ducks Oxyura leucocephala - Κεφαλούδι, are regular but very rare winter visitors of Northern Greece large wetlands. Most seen in Lake Vistonida, one has to be very careful to figure them out among the numerous Pochards, Tufted and other ducks. In the past several hundreds could be seen, but nowadays their numbers are much reduced. 
This poor photo was the best I could do as it was getting dark and the birds were too far to be decently photographed...
