The term 'COB and PEN' is a reference to the traditional job of swans, which is to guard and protect their territory. Swans are known for their territorial behavior, and they will often use their beaks and wings to defend their area from intruders. The term 'COB and PEN' is derived from the Old English words for 'COMB' and 'PEN, ' which refer to the swan's COMB-like beak and its ability to PEN in its territory. This term is used to describe the swan's protective nature and its willingness to defend its home.