Even though she may have not been engaged in nest building prior to this year, she still has the natural ingrained behavior to nest. She may even be bored and just pulling at the nest which she will eventually abandon in a short time.

Now, having said this, if she begins to exhibit egg laying behavior and strains, but produces no eggs, you may want to have her examined by an avian veterinarian to ensure that she does not have egg impaction. Usually, this condition will only occur if a swan has a mate and goes through the mating/nesting ritual. However, stranger things have occurred. More than likely, she is fine and will abandon the nesting behavior shortly. The Regal Swan