Fwooper

 The Fwooper is a magical African bird with brightly-coloured feathers, which can include orange, pink, lime green and yellow. Listening to the Fwooper's song will drive the listener insane, so each bird must be sold with a Silencing Charm placed on it. The Charm has to be reinforced monthly, and a license is required to own one of the birds.

Fwooper feathers are used as quills, and they lay patterned eggs. The number four, in runic Uric the Oddball once tried to convince the Wizards' Council that the Fwooper song was actually beneficial to a Wizard's health, and listened to it continuously for three months. His presentation did not go well, when he turned up wearing nothing but a toupee that, on closer examination, was revealed to be a dead badger.

The four colour varieties of the Fwooper are used to represent the number four, in the runic alphabet.