The swan was scared enough after the encounter with the child so that she is now not only protecting herself, but also her habitat from anyone that might come into contact with her or you.

Place two chairs in the yard and begin to feed her near the chairs with bread and a water bowl. Once she becomes comfortable with this scenario, you need to slowly introduce someone else to her while you are present. If she tries to attack the person, step in and say no very loudly while also grabbing her gently. Repeat as required.

She needs to relearn that people in your presence are okay and not to be fearful. The worst thing that may occur is that she will stay away from all people including you, but if you add chairs which allow you and the guest to sit quietly and feed her, this may get her retrained into knowing that while you are around, attacking is not needed or appropriate. Please let us know how this situation progresses. The Regal Swan