The female swan will leave the nest to bathe, preen, eat and drink. The male swan will stay nearby, not necessarily on the nest, but nearby as the female takes a rest.

Once hatching of the eggs are imminent, the female will take fewer rests and spend less time away from the nest. While she leaves the nest, she will cover the eggs with as much vegetation from the nest as possible so predators cannot find the eggs. This is probably the reason that you are not seeing the eggs. The eggs are buried under the vegetation at the bottom of the bowl of the nest.

If there is something wrong with the eggs, the parents will roll them out of the nest and dispatch them into the water or as far as possible from the nest so as not to attract pests such as ants or mice or predators, i.e., raccoons, foxes, etc.

As long as there are no predators in the area, domestic or wild (dogs, cats, bobcats, etc.), the parents will return to the nest until the eggs hatch. So, as long as the parents are still tending the nest and the female is still sitting, it means that there are viable eggs. Nature does not allow for grieving or sitting around on a nest waiting for something that is not going to occur.

The Regal Swan