This is a tough situation especially since your state and many others will kill the birds if you take them to a veterinarian or wildlife facility. Therefore, it is going to be up to you or someone else with the possibility of violating laws to care for the birds.

This is why we would first suggest that you check the legal ramifications for the care of the birds. Then, if you can care for them, we would suggest that you leave them in the normal environment as long as possible, bringing them both in during the winter. A shed or garage, free from chemicals, gas, etc., free from predators and pests (ant, rats), with adequate ventilation, but no direct draft, with a water feature and straw on the floor will work well. You will need to keep their food, straw and water changed daily and water the birds fully with warm water so they can continue to preen and keep their feathers clean and water repellent. They will be able to live in warmth during the winter and then place them back on the pond in the springtime after the pond unfreezes and temperatures rise. As long as the birds can fend against the coyotes and other predators, they should be fine. However, a frozen pond will make access by predators easy and therefore, the birds cannot survive on a frozen pond not only because of lack of food and water, but also the predators. It is best to keep the birds together if at all possible. We wish you well with this situation and thanks for caring. The Regal Swan