The tufted duck is a medium-sized diving duck, smaller than a mallard. It is black on the head, neck, breast and back and white on the sides. It has a small crest and a yellow eye. In flight it shows an obvious white stripe across the back of the wing. It breeds in the UK across lowland areas of England, Scotland and Ireland, but less commonly in Wales, with most birds being residents. Numbers increase in the UK in winter because of birds moving to the UK from Iceland and northern Europe.
Read more at https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/bird-a-z/tufted-duck/#DZ70d1UlRT9xkJVQ.99