Ask the Swan Specialist
Date: 21 May 2017
Sometimes, female swans will (double clutch), lay another set of eggs should something happen to the first eggs. She may or may not lay the exact number to replace, but lay 1-2 on the new nest. If she is still sitting on the nest, then there is a possibility that there are eggs in the new nest and the mom swimming away from it allows her to rest, eat and bathe. As the eggs get closer to hatching, the distance and time spent from the nest will shorten.
There is also another possibility in that nature requires swans to nest and the female is fulfilling this need even though there are no eggs. No matter which scenario, the female will not keep sitting for long if there are no eggs or the eggs are non-viable. The Regal Swan