DESCRIPTION:
Grey Heron is a large bird with rather grey plumage. The long, dagger-shaped bill is rather orange. Eyes are yellow. Legs and feet are deep pink.
Standing as still as a statue at water edge, exhibitionist enjoying the sun, fearsome dagger when a fish approaches, or wonderful bird with slow and quiet flight, the Grey Heron always amazes.
And when the breeze plays through its slate-grey or bluish-coloured plumage, raising the long pale back feathers or the delicate black aigrette, it is the whole bird which seems to be carried along by the wind.
Closely related to the wetlands, the Grey heron is a character that arouses a great interest.
Adult in breeding plumage has grey upperparts with elongated paler feathers on scapulars. Flight feathers are black.
The underparts are whitish. The white foreneck is streaked black. We can see white elongated feathers on the breast.
On the head, crown, cheeks, chin and neck sides are white. A broad black stripe extends from the eyes to the nape and is prolonged by long black aigrets.
Adult in non-breeding plumage is slightly duller. It lacks the long feathers on scapulars, breast and nape. The bill is rather yellow. Legs and feet are yellowish-brown.
Both sexes are similar, but female has shorter aigrets.
Juvenile is greyer, without black markings on head and breast. General plumage may be more or less dark. Legs are duller, mostly dark greyish-brown. The bill show grey upper mandible and yellowish lower mandible.
SUBSPECIES:
We can find four subspecies (A.c. cinerea ; A.c. jouyi ; A.c. firasa ; A.c. monicae) which differ in size and plumage, mainly on neck, back and wings. Race monicae is much paler.
HABITAT:
Grey Heron may live in several kinds of habitats with shallow fresh, brackish or salt water. It may be found in open areas, but it needs some trees for nesting. Inland, it is often seen near rivers, lakes, marshes and rice fields. Along the coast, it frequents estuaries, mangroves and tidal mudflats.
It is usually seen from sea-level up to 500-1000 metres of elevation, but according to the range, it may be seen up to 2000 to 3500-4000 metres.
RANGE:
Grey Heron is relatively common resident and widespread in most part of Europe. It is also found in Asia and some parts of Africa. We can observe northern bird’s migration southwards during hard winters.
BEHAVIOUR:
Grey Heron, as many Ardeidae, may stay motionless during long time at water edge, waiting for prey. It is a passive feeder, standing on one leg, with neck sunk between shoulders.
If alarmed, it stretches its neck, motionless and watchful, and may take off immediately.
Grey Heron may also hunt in crouched posture, with body and neck parallel to the ground or the water. When the prey is close enough, it spears it with its bill.
It also walks slowly in shallow water or at the edge, watching for preys.
It may use its wings to frighten the prey by alternated open and close wings, or use them as an umbrella, in order to attract the prey into the shade, but also to reduce the light for better visibility.
It also may use its feet, sinking one foot into the water or the mud in order to frighten the prey, or use the “foot-stirring” by vibrating one leg in the same way.
Usually, the Grey Heron swallows its prey whole and head first, and the time is determined by the size of the prey.
It usually feeds alone and defends its feeding area, but sometimes, we can see small groups feeding together at abundant food sources.
When in flocks, Grey Herons walk on line, mainly at dusk, gleaning here and there. At this time, particularly in autumn, they search for insects, but also small rodents and frogs.
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 enters 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-bonds lack only one breeding season.
FLIGHT:
Grey Heron flies with slow and heavy wing beats, and the wings strongly arched and trailing legs. The neck is tucked into the shoulders.
REPRODUCTION:
Breeding season varies according to the range.
Grey heron breeds in colonies, often mixed with other species in the same trees.
The nest-site is usually in tall tree, in reedbeds or bushes. The subspecies A.c. monicae nests on the ground.
The nest is a platform made with sticks or reeds, 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.
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 1 to 10 white or pale blue eggs, 4-5 in average in Europe. Eggs are laid each two days. Incubation by both parents lasts about 25-26 days. Altricial chicks are covered with brownish-grey down with whitish underparts. They usually have tousled crest.
They are fed by both adults. Parents care their young attentively. During the first 20 days, an adult remains at nest to keep an eye on the young. Male and female incubate by turns four times a day, always with the same display. Young are protected from sun and rain.
Young are fed by regurgitation by adults into the mouth. They fledge about 50 days after hatching, and they remain 10 to 20 days more at nest.
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.
DIET:
Grey Heron feeds mainly on fish, but according to the range and the season, it also may consume amphibians, crustaceans, molluscs, aquatic invertebrates, snakes, rodents and small birds. It may sometimes take some vegetal items.
PROTECTION/THREATS/ STATUS:
Grey Heron is vulnerable to hard winters with frozen waters, and northern populations have an important mortality during these cold periods. However, this species shows a good recovery in following years.
Grey Herons are killed by hunting and trapping.
But the species is threatened by changes in the habitat with drainage of wetlands, deforestation and disturbances at nest-site.
This species is strongly protected, and numbers are increasing in most parts of the range. At this moment, populations are stable and not globally threatened.
Sources :
HANDBOOK OF THE BIRDS OF THE WORLD vol 1 by Josep del Hoyo-Andrew Elliot-Jordi Sargatal – Lynx Edicions – ISBN: 8487334105
THE HANDBOOK OF BIRD IDENTIFICATION FOR EUROPE AND THE WESTERN PALEARCTIC by Mark Beaman, Steve Madge – C.Helm – ISBN: 0713639601
THE COMPLETE BOOK OF BRITISH BIRDS – Written by “Royal Society for the Protection of Birds” experts – Préface de Magnus Magnusson – Michael Cady- Rob Hume Editors – ISBN: 0749509112
