I live near private lake where there are two swans I visit for over 10 years. Each year they nest and with 1-2 surviving cygnets during first 6 months. Then, babies fly off,usually, by late November. But this year, the babies were always there with their parents, up till yesterday, Jan.7th. It was the last time I saw the youngsters (sister and brother) when I came to feed them. It was getting colder yesterday and even more freezing during the night. By this afternoon the temperature has dropped to wind-chill -24F. When I came today the entire lake got frozen except small area where I found the parents,but no sight of their youngsters. I looked everywhere and have spotted some animal's footprints on the ice along frozen waters. I also saw large swans' footprints almost at the same spot where other land animal left their print. I was saddened thinking that both youngsters were killed by a predator while on ice. But then I thought it doesn't look as it was any kill or fight since there were no feathers or blood evidence to find. I wonder: is it possible that the youngsters just flew off because of the cold coming or is it possible that they were grabbed and carried away by some predator? I feel so sad. I am so used to this family and feel so bad for feeding them all and the babies since their birth. If the youngsters flew off-they will not survive because there wouldn't be fresh,organic daily bread found . Right? Please, someone, explain me what could have happened? Thanks.