We have a mating pair of swans, and this year they hatched two cygnets (we had a mid March freeze that may have frozen the other six eggs). The two cygnets have been healthy and eating and growing well. They were five months old. Yesterday morning we found one of them dead floating in the pond with its head tucked under its wing as if it were asleep. A friend who is a wildlife expert fished the dead bird out of the lake. We had expected to see some injuries, but found nothing. The throat was clear and our friend sliced the bird open and found nothing upon examination that would give us a clue to its death. This bird was eating and behaving as usual the at dusk the night before. Do you have any ideas what could have happened? There had been no territorial disputes as that doesn't usually happen until November. At that time, in the past, for previous offspring, we have separated the juveniles from the parents.

And while I have you, why do we see multitudes of swans living together in harmony in Europe, but here our adults attempt to kill or drive off their offspring when they cygnets reach 6 ot 7 months old.