The grey heron breeds either solitarily or in colonies, called heronries, in woodland close to water. The heronries are usually traditional sites used by successive generations. The flat nest of sticks is built in the crown of the tree early in the year, and four or five eggs are laid towards the end of March, though often earlier in mild winters. Both parents share the duties of incubation, which takes 25 to 26 days. The young, which are covered in down in their first days of life and are fed on regurgitated fish, fledge after 20 to 30 days.
