We're not sure about the statement regarding poor nutrition and reproductive health. Although this might be a possibility, there are other possibilities which may be more probable.

First, either or both of the swans may have a reproductive disorder, meaning either or both could be sterile.

Second, a more probable cause may be that you do not have a male and female swan. People purchase swans and the sellers may have used less reliable means of conducting sexing such as probing. Probing is not reliable because the male's penis or penile node may not be seen or felt during the probing if the swans are very young birds and the organ is not developed.

Females will mate and will produce eggs. Obviously, the eggs will not be fertile. Swans will stay on the eggs until they figure out that the eggs are not fertile. If you remove the eggs, (trying to get the female to leave the nest and eggs), you will probably not only fail to remove the swan from the nest, but you may cause her to "double clutch".

Female birds are programmed to produce a certain number of eggs during the mating season as well as during her entire life. Swans can count and if you remove an egg, the female may replace the egg or eggs (double clutching). This can be detrimental to her health as female swans lose approximately 30% of their overall weight during the nesting season. The female swans will sparingly eat, bathe and swim during the nesting season so if she loses more weight or energy, she could become prone to illness or disease.

The "male" swan you describe may still be a female who is responsible for protecting the female that is laying the eggs.

All states have different laws requiring swan ownership and breeding. You may need to check the law regarding breeding. If there is no viable young being produced, you may not need a permit as there is no breeding. Additionally, if you have had the swans for some time without a permit, you may be grandfathered in regarding ownership. However, if in doubt, we would suggest that you contact your local wildlife officials.

As far as the defensive behavior from the protective swan, welcome to swan ownership! Dr. Jekyll becomes Mr. Hyde during mating and nesting season because swans are so protective of their mates and good parents. So, you will have to endure this behavior until their hormones stabilize and all returns back to normal. We hope this information is of benefit. The Regal Swan