wood pigeon and ring neck dove paired?

We have nine types of bird feeder and attract many varieties of bird to the garden.

However this past week we have a huge wood pigeon and a tiny ring necked dove that have quite clearly paired up. They always fly in together and equally leave together. They roost in the lilac together. The pigeon very forcefully chases any other male pigeons away.

Is this strange pairing normal or something quite unusual?