I read your post RE: the swan left behind. I live in a state that gets very cold as well. I have lived on a lake all of my life, and it freezes throughout the winter. We have had a mother & father mute swan that have had babies over the years. Some of their offsprings have certain injuries.1- has a broken wing, the other has the same plus an injured leg. Neither of which can fly away during the winter. They stay all year round. We do have several creeks nearby. Running creeks don't freeze. But they always manage to stay on the snow right in front of the frozen lake. He might b injured & can't fly or hasn't practiced flying.parents teach them that. Try & lure him to the shallowest end towards you by throwing down whole kernel dry feed corn as opposed to bread. bread expands in the stomach & doesn't have much nutritional value. By doing this, your training him to gain your trust. once he starts to eat the corn start throwing it down out of the pond closest to you. Then get a bowl of warm water & put the corn or cracked corn in that. Feed him this way once the lake freezes. he should b fine:) protect him