Grey Heron

The grey heron (Ardea cinerea) is a large, long-legged heron widespread across Europe, much of Africa and large parts of Asia. Adults are about 90–98 cm long, weigh roughly 1.0–2.0 kg and have a wingspan of approximately 175–195 cm. Males average larger than females, but the sexes are otherwise similar.

Adults have grey upperparts, a pale neck and head, black shoulder and flank markings and a broad black stripe behind the eye that extends into long crest plumes. The long, dagger-like bill is usually yellowish and becomes brighter during the breeding period. Juveniles are duller and greyer on the head and neck and lack the fully developed black crest. In flight the neck is pulled back into an S-shape, unlike storks and cranes, which normally fly with the neck extended.

Grey herons use an exceptionally wide range of habitats wherever suitable prey is available. They are strongly associated with rivers, lakes, marshes, ponds, estuaries and coasts, but also use wet meadows, farmland, urban parks and other terrestrial habitats some distance from open water.

Fish are important prey in many populations, but the species is an opportunistic predator rather than a strict fish specialist. Amphibians, crustaceans, molluscs, insects, worms, reptiles, small mammals, young birds and other available animals are also taken.

A 2024 study of breeding colonies in Poland found that the non-fish component of the diet varied with surrounding habitat and local prey availability, underlining how flexibly the species switches among prey types.

Grey herons use a broad and coherent foraging repertoire. The classic method is to stand motionless or walk slowly in shallow water before striking rapidly with the bill, but birds also stalk prey through grassland, probe and search along shorelines and exploit temporary concentrations of food.

Technique changes with habitat, water depth and prey type. In tidal habitats, birds may feed at nocturnal low tide as well as by day, following the periods when prey is most accessible. This flexibility allows the same species to hunt successfully in open water, marsh edges and terrestrial habitats.

Grey herons are often solitary outside breeding colonies and can defend particularly productive feeding sites from other herons. Activity is often greatest during daylight, but the species is not strictly diurnal and may remain active well after dark where conditions are favourable.

At rest the long neck is frequently held partly retracted, while in flight it is folded into the characteristic S-shape. Birds commute regularly between feeding areas, roosts and breeding colonies and may travel several kilometres between them.

Movement patterns vary strongly across the range. Many birds in western and southern Europe and in warmer parts of Africa and Asia are resident or make only local movements, while populations from colder northern and eastern regions are more migratory. Juveniles can disperse widely after leaving the breeding colony.

Cold winters have an important effect on northern populations because prolonged ice reduces access to shallow-water feeding sites. Ringing and long-term monitoring show that severe winters can cause substantial short-term mortality and population fluctuations.

Grey herons usually breed colonially in traditional heronries, sometimes containing many nests. Nests are most often built high in trees but may also be placed in shrubs, reedbeds, on cliffs or other suitable structures. Both adults add sticks and other plant material, and established nests can be repaired and reused over successive years.

Pairs are usually monogamous through the breeding season, but multi-year pair bonds also occur. A study published in 2013 of a colony in Tokyo documented several marked pairs remaining together from year to year while both birds were present.

The typical clutch contains three or four eggs, although two to seven are recorded. Both parents incubate for about 26–27 days and feed the young by regurgitation. The chicks remain in and around the nest for roughly 50–55 days before fledging. Breeding timing varies geographically; in Norway eggs are laid mainly from late March to mid-May.

Juvenile mortality is high. In Norway only about one-third survive to one year of age. Among birds that reach breeding age, British ringing data indicate a typical life expectancy of about five years, but individuals can live much longer. The BTO longevity record is 23 years and 9 months, and a Norwegian ringed bird was found dead about 24 years after being ringed as a chick.

The grey heron is classified as least concern on the IUCN Red List. The global population is estimated at approximately 500,000–2.5 million mature individuals, while the overall global trend remains uncertain.

In Norway, the 2021 national Red List also classifies the species as least concern, with monitoring data showing no indication of a national decline at the time of assessment. Regional patterns can differ: the 2025 assessment for South Africa, Lesotho and Eswatini retained Least Concern but found a declining regional trend, with an estimated range reduction of around 10% over three generations. Wetland loss, disturbance, water pollution, persecution and severe weather can therefore remain important locally even for this widespread species.