What is a female swan called?

Swans are birds of the family Anatidae within the genus Cygnus. The swans' close relatives include the geese and ducks. Swans are grouped with the closely related geese in the subfamily Anserinae where they form the tribe Cygnini. Sometimes, they are considered a distinct subfamily, Cygninae. There are six or seven species of swan in the genus Cygnus; in addition there is another species known as the coscoroba swan, although this species is no longer considered one of the true swans.

The English word 'swan', akin to the German Schwan, Dutch zwaan and Swedish svan, is derived from Indo-European root *swen (to sound, to sing). Young swans are known as swanlings or as cygnets. An adult male is a cob, from Middle English cobbe (leader of a group); an adult female is a pen.