These popular birds have successfully raised cygnets on the Wharfe, but if you get too close, you’ll see behaviour that contrasts with their usual grace and calm. They are called “Mute” because they are less vocal than other swans, but as well as the aggressive hissing at threats, they make a loud noise with their wings in flight. This is a bit like a foot pump blowing up an airbed, and performs the function of keeping the birds in contact with each other. Combined with their size (one of the heaviest flying birds), and with their long necks straight out in front of them, it makes for an impressive sight. For centuries, Mute Swans were domesticated for food, with ownership being marked by nicks in their webbed feet or beaks, a fact which explains the confusing name of the “Swan With Two Necks” pub where I used to drink as a student in Woodhouse, Leeds. Non-marked swans belonged to the Queen. Ironically, this domestication may well have prevented the extinction of the bird in Britain through over-hunting.