Yes, female swans have a programmed amount of eggs that they will lay during their lifetime and each nesting period. Typically in birds, the younger the female begins to lay eggs, the younger she stops the process. Conversely, the later the onset of egg laying, the later the process ceases.

With the continual cold and warm fronts that have been pushing through the continental U.S., some birds are being delayed in their nesting and mating behavior. So, it may be that your swans are a little late this year in nesting. The Regal Swan