You might try to see if you can find the manager of the pond or a wildlife rescue facility near you. They will need to access the ice by boat (carefully as not to capsize and fall in the water) to break the ice and get to the swan if she is frozen. Otherwise, if the swans are not eating or moving, they can drown, starve or be attacked by predators which can access the birds on the ice. If all else fails, see if the local fire dept. might try to help. The Regal Swan