The swans may not be able to leave the ice. This inability to leave is extremely dangerous for the swans as they may freeze, drown, starve or be attacked by a predator that can access the pond by walking on the ice.

We would suggest that you contact a wildlife rescue group to see if they can safely access the ice to free the birds. If the temperature is going to warm in order for the pond to unfreeze in the next day, the birds may be okay. However, if the freeze is going to last or worsen, then the birds may need rescuing. The Regal Swan