Why does the queen own the swans?

Whilst I agree with the technicalities of the legality, and propriety ownership of swans by the crown in the Uk. I do disagree with the previous poster on how palatable swan is.

It is extremely fishy, oily meat, and, whilst pre-victorian era UK gentry considered it a delicacy, by the time Victoria came to the throne, it had fallen out of favour. So, whilst Cygnets are owned by the Crown (note, CROWN, not Queen Elizabeth herself. (Subtle, but important)) and to eat them is, technically, treason in the UK, they do not taste very nice to a modern palette.