Unfortunately, if the coyote took the male, it will try to come back and finish off the female. Unless you place the female indoors for a couple of days and nights, the coyote will be successful. To introduce another swan in this habitat, you will need to pen the new swan 1/2 in the pond and 1/2 on water with a feeder inside. The pen will need to be enclosed top to bottom so that no predator can dig under the pen or climb into the pen. This would be extremely stressful for a new bird if the coyote should keep circling the pen trying to gain access. Once the swan is released on the pond, if it still has the ability or will to sit on the bank at night or during the time that the coyote prowls, would only set-up the new and old bird for an attack. We would suggest not to reintroduce a new swan at this time and to try and provide a means to protect the female swan should the coyote return. Even if you introduced a new male, there are no guarantees that the female will accept a new mate. The Regal Swan