We have a pair of very attentive black swans who have 4 cygnets - 5 weeks old. The parents have fussed over the one which is at the waters edge - not moving much. It seems to be the same size as siblings and no apparent problems. The parents leave and then come back to check on it, then stay close by most of the time. What do you recommend we do if anything. We're tempted to bring it in for safety measures overnight.