The Mute Swan (Cygnus olor) is identified by the black knob on the top of the beak. A female Swan is known as a 'pen' and a male is a 'cob'. 

Both males and females are involved in parenting; the cob will guard the nest while the pen leaves to feed, but will not incubate the eggs. Both parents are devoted to the cygnets, which, with their downy, brown fluff and short necks, do indeed look like the 'ugly duckling' of the rhyme! However, they soon grow into their adult plumage.

The Whooper Swan (Cygnus cygnus) is a large migratory winter visitor to the UK, primarily arriving from Iceland in October and leaving by April.