We have a pair of mute swans on our private lake which produced 8 babies at the end of April. Someone removed two of them last week and gave them to an individual to put on his own lake. We are all perturbed about this as we are not sure that these young swans can survive at this stage without their parents guidance. I do not even think that they can fly yet. How long does a cygnet have to stay with its parent before it is self sufficient?