This gem of information came up in the course of class today.
A female swan is called a pen.
As a teacher you are always trying to push the boundaries and so I asked the question
"Does anyone know what a male swan is called?"
There was a silence while they tried to retrieve an answer from the recesses of their brains. Not wanting to leave me waiting too long, a voice came from the back of the classroom.
"Eh, would he be a Ballpoint?"