Eastern England, the fens. A car bumps down a grassy track, alarming the old farm horses. A man punting frightens a grebe off her nest, and a man sailing a dinghy scares a coot. The bittern makes her nest in this contested place, as far as she can from the haunts of human beings.

Bitterns are said to be easily scared. The bird is notable for its remarkable feathering and appearance. A female bittern tends her eggs, adjusting them on her return to her nest in the reed beds, and, after one chick and then others hatch, feeding them. Their begging and scratching at her beak prompts the female to regurgitate fish and frogs. Empty eggshells are disposed of and the chicks appear to accidentally eat reed stalks.

Bitterns fly, crossing open water and reed beds. The male takes no part in rearing young and spends his time hunting and fishing in the reeds. A suited man, with a servant or local a few steps behind him, advances through chest-high reeds. A male bittern adopts a defensive posture, with splayed wings, puffed throat and open bill.

The female continues to feed: a day in the life of a bittern chick amounts to one long meal. A man punts against the darkening sky as dusk encroaches, and the bittern "rejoices in the quiet of the fens".