We have many lakes with a light on at night. It does not hurt the swan and will allow it to see predators. Yes, they can also see him, but as long as the pond does not completely freeze so the predators can't walk onto the ice, this should not be an issue. It allows the swan to see the predators and seek deeper water for shelter. In the dark, the swan may not be able to see the predator before it is too late. The Regal Swan