Actually, the new pair should have been penned. Think about having someone come in and take over your house. This is where the problem is beginning. The new pair should be penned to acclimated themselves to you (the caretaker), how they are going to be fed (feeder system), the new habitat and the older swan who resides in the new habitat.

Even though they have separated, they still could fight, but it is not likely that the male will hurt her. In the wild, males will not usually hurt a female intentionally. Now, he could chase and nip at her tail feathers or even try to mate with both of the females. He might even try to mate with her and not the other female depending on the age and if they had bonded. In any case, watch them closely to see if things work out. If there is continued aggression where it appears that the swan may get hurt, you may have to place a barrier on the pond to keep them separated. But, again, this is her home and to relocate her would not be the best solution. The Regal Swan