We have a pair of mute swans which nest every year on the village pond.

In the past, they have laid a clutch of between 5 and 8 eggs and hatched them successfully, with one or the other adults sitting on the nest more or less continually for the 35 - 40 day incubation period.

This year we have had an exceptionally cold and prolonged winter, and they are late laying. They are very used to people, as we get a lot of visitors to the village at weekends.

Last weekend, when an adult stood up (to stretch its legs perhaps?) I noted and photographed two eggs. Later that day I noted and photographed three eggs.

In the last few days when it has still been very cold (sub-zero at night and about 3-5deg. C during the day) the adult swans have left the nest for significant periods. The nest appears either devoid of eggs or they have covered them.

Is this usual or could there be a problem this year?