The only reason why i say it might be an owl is because i brought it up to a few avid hunters, thats what they suggested, and they tell me that coyotes go for the inside like heart and liver. I saw what a coyote did on two occasions as well. I have absoulutely no bob cats or cats of any kind, i live in the Hudson Valley area of NY state.I have never seen a fox on the property and i am not sure if they will swim out to an island. But they are sneaky.
No one will take a lone female swan that i know of. When you say repaired you mean emotionally? ... I might be able to run some electric wire...