Three or four is an average clutch, but I've seen six eggs in a nest near Reedham. The eggs take 27 days to hatch and the young remain in the nest seven weeks. The history of some Norfolk heronries is well documented. One of the oldest and perhaps most famous for the 'sport' its herons provided falconers is at Didlington. It is still occupied today.
Herons suffer greatly during severe weather and the majority of ringing recoveries are in winter.
But starvation is not the only cause of death. Recovery reports have included examples 'caught in telephone wires,' 'found dead outside fox's earth,' 'caught on barbed wire' and 'shot poaching goldfish'. The longest living individuals have attained 25 years. Not all herons are sedentary risking starvation in cold spells. Locally ringed birds have been recovered in winter in France, Spain and Portugal when emigrants marked in Norway and Sweden appear in Norfolk.