[order] Ciconiiformes | [family] Ardeidae | [latin] Ardea cinerea | [UK] Grey Heron | [FR] Héron cendré | [DE] Graureiher | [ES] Garza Real | [IT] Airone cenerino | [NL] Blauwe Reiger

Blauwe Reiger determination

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Large, heavy-billed, long-necked, deep-bodied, and long-legged piscivore. Whitish head and neck contrasts with grey wings and black-sided body. In flight, wing coverts show whitish marks along leading edge, and grey coverts contrasting with almost black flight feathers. Juvenile has fully black crown and dingier plumage.

Normally closely linked with distribution of suitable waters and trees, being more arboreal than other west Palearctic herons except Night Heron. Prefers shallow fresh waters, standing or flowing, including broad rivers, narrow streams (not too rapid), oxbows, deltas, marshes, and estuaries; also lakes, pools, floodlands, muddy and sandy shores or flats. Nowadays a common visitor of urban areas, searching for garden ponds and fish dumps.

Ardea cinerea is a widespread breeder across much of Europe, which accounts for less than a quarter of its global breeding range. Its European breeding population is large (>210,000 pairs), and underwent a large increase between 1970-1990. Although there were declines in the Ukrainian population during 1990-2000, most other European populations-including sizeable ones in France, Germany and Russia- increased or were stable, and the species underwent a moderate increase overall.

Grey Heron feeds mainly on fish, eels and batrachians. It also may consume small rodents, insects, crustaceans and reptiles. It hunts on the watch, perfectly motionless. With great speed, it tenses its neck and its dagger-shaped bill jabs the prey. Adults require 350-500 gram of food daily.

This species has a large range, with an estimated global Extent of Occurrence of 10,000,000 km². It has a large global population estimated to be 710,000-3,600,000 individuals (Wetlands International 2002). Global population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern. [conservation status from birdlife.org]

Grey Heron's courtship display is an elaborated ceremonial. Heron arriving at nest erects its crest, while it utters a loud, hard call. The one occupying the nest answers with stretching neck upwards, and moving it back and forth, with bill pointed upwards and crouching, in order to have its body at the nest level. Then, it bends the neck, with the head at legs' level, and snaps noisily the bill. Actually, this ceremonial is a call to the male with insistent manner from the old nest, using the same movement and taking frequently a twig into the bill. If a female approaches and enter strongly into the nest site, she may be immediately evicted from the nest by the male. Females have to adopt a shy and gentle attitude to win the male's trust. When one is accepted, male snaps the bill from 20 to 40 times. Pair lasts only one breeding season.
Grey Heron builds a very large nest with dry twigs, branches and sedges. Materials vary according to the habitat. The interior of this large structure is a cup fashioned with twigs, cattails and grass. This nest may serve year after year. Grey Heron nests in large colonies, with numerous nests on one tree. Male brings materials and female remains at nest almost the day long, assuming the construction weaving branches and sedges. When the male comes back to the nest, we can see the courtship display's ceremonial, including during incubation period. Female lays 3 to 5 dull grey-blue eggs, sometimes with some reddish tint. Eggs are laid each two days. Incubation lasts about 26 days, shared by both parents. When they hatch, chicks have comic appearance, with dense down on head, as a large crest and are fed by both adults. During the first 20 days, an adult remains at nest attending the young. Male and female incubate by turns four times a day, always with the same display. Young are protected from sun and rain. Chicks give some small knocks to parents' bills, and adults regurgitate food directly into their mouths. Young are able to fly at about 55 days old. Grey Heron produces only one brood per year, rarely two, except if the first clutch is destroyed. In this case, another clutch comes quickly after destruction of previous brood.

Populations of extreme N migratory, further S tend to be sedentary or dispersive; marked post-breeding dispersal (see page 392). In Palearctic, migratory tendency increases towards N and E; breeding populations of Iberian Peninsula, Britain and Ireland are sedentary, but others E to Siberia mainly migratory, though some individuals overwinter on breeding grounds; most migration towards SW, more rarely towards S or SE, starting Sept/Oct, with return starting in Feb. Birds of Far East migrate to S China; 2 birds ringed in SE Siebria recovered in N Thailand, partial migrant in Japan. Populations of Africa, India and SE Asia sedentary. Vagrant to Spitzbergen, Greenland, Lesser Antilles, Brazil. At Lac de Grand Lieu, W France, birds commute 2-38 km between colony and feeding territories.