We are very sorry for your loss. Do you know what killed the swan? Yes swans like all animals do grieve, but it is different than humans in that nature does not allow for extended grief. To do so, would jeopardize more members of the group. She will get along just fine by herself. The major issue is to prevent her from being killed. Should you try to introduce another swan, you need to make provisions for protecting both swans. If you introduce another swan, there are no guarantees that the swans will get along. So, if you decide not to get another swan, she will do just fine on her own as long as she is protected from predators, especially at night. The Regal Swan