Are you absolutely sure that your male swan was the one killed? Did you have DNA Sequencing conducted on your remaining swan and the introduced swan? DNA Sequencing is the only reliable method of determining gender.

The reason that we asking this question is that your swan, if it is a female, is not behaving like a female swan. Usually, (not always, but usually) female swans will accept another male as a mate if something occurs to the original mate.

Male swans (usually, but not always) will not accept another mate if something should occur to the original mate.

Female swans usually do not attack or act defensively as male swans and will certainly not try to grab tail feathers and sit on a male. If this new swan is a female, then your female (if it is a female) may be trying to rid her habitat of another female as this is seen as competition for the habitat.

Now, if this new swan is a male, he will exhibit this behavior trying to mate with your "female" swan. This sitting on the swan may be mating behavior if you have swans of opposite gender.

If your remaining swan is a male and the new swan is a male, then you are going to have a continual fight on your hands until one or both become seriously injured.

You need to immediately check each swan for gender prior to placing them on the lake together. The person providing you with the new swan should have provided you with appropriate veterinary and gender (DNA testing) documents.

If the swans are opposite gender, you need to keep the new swan in the pen for at least 2 weeks until things settle down and they begin to accept each other. Even then, when releasing the new swan onto the pond, you need to have some type of rescue equipment, i.e., boat, kayak, etc., so that you can effect a rescue.

If a rescue should be required, you need to return the new swan to its previous owner or try to find a safe adequate new home for the swan. Continual defensive behavior between the two swans is a good indicator that this pairing is not going to work. Again, not all lone swans will accept another mate.

We hope that this information is of benefit. Please let us know how this situation progresses. The Regal Swan