Thai National Parks

The grey heron (Ardea cinerea), is a wading bird of the heron family Ardeidae, native throughout temperate Europe and Asia and also parts of Africa. It is resident in the milder south and west, but many birds retreat in winter from the ice in colder regions. It has become common in summer even inside the Arctic circle along the Norwegian coast.

Description

It is a large bird, standing up to 100 cm tall and measuring 84 - 102 cm long with a 155 – 195 cm wingspan. The body weight can range from 1.02 – 2.08 kg. Its plumage is largely grey above, and off-white below. Adults have a white head with a broad black supercilium and slender crest, while immatures have a dull grey head. It has a powerful, pinkish-yellow bill, which is brighter in breeding adults. It has a slow flight, with its long neck retracted (S-shaped). This is characteristic of herons and bitterns, and distinguishes them from storks, cranes and spoonbills, which extend their necks. The call is a loud croaking "fraaank". The Australian white-faced heron is often incorrectly called a grey heron. In Ireland, the grey heron is often colloquially called a "crane".

Food and feeding

It feeds in shallow water, catching fish, frogs, and insects with its long bill. Herons will also take small mammals and reptiles. They have also been observed catching and killing juvenile birds such as ducklings, and occasionally take birds up to the size of a water rail. Due to its S-shaped neck, the bird is able to strike with the bill very rapidly. It will often wait motionless for prey, or slowly stalk its victim.

City life

Grey herons have been able to live in cities where habitats and nesting space are available.

In the Netherlands, the grey heron has established itself over the past decades in great numbers in urban environments. In cities like Amsterdam, they are ever present and well adapted to modern city life. They hunt as usual but also visit street markets and snackbars. Some individuals make use of people feeding them at their homes or recreational fishermen to share their catch. Similar behaviour on a smaller scale has been reported in Ireland.

Herons have also been observed colonising water enclosures in zoos, such as spaces for penguins, otters, pelicans and seals, and taking food meant for the animals on display. Such behaviour has been noted in zoos in Vienna, London and Amsterdam.

Breeding

This species breeds in colonies (heronries) in trees close to lakes, the seashore or other wetlands, although it will also nest in reedbeds. It builds a bulky stick nest.

Parasites

A thorough study performed by J. Sitko and P. Heneberg in the Czech Republic in years 1962-2013 suggested that the central European grey herons host 29 helminth species. The dominant species consisted of Apharyngostrigea cornu (67% prevalence), Posthodiplostomum cuticola (41% prevalence), Echinochasmus beleocephalus (39% prevalence), Uroproctepisthmium bursicola (36% prevalence), Neogryporhynchus cheilancristrotus (31% prevalence), Desmidocercella numidica (29% prevalence) and Bilharziella polonica (5% prevalence). Juvenile grey herons were shown to host fewer species, but the intensity of infection was higher in the juveniles than in the adult herons. Of the digeneans found in central European grey herons, 52% of the species likely infected their definitive hosts outside of the central Europe itself, i.e., in the premigratory, migratory or wintering quarters despite the fact that a substantial part of grey herons do not migrate to the South, particularly in recently repeatedly occurring warm winters

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