White-necked heron | |
---|---|
In Edithvale Wetland, Melbourne, Australia | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Pelecaniformes |
Family: | Ardeidae |
Genus: | Ardea |
Species: | A. pacifica |
Binomial name | |
Ardea pacifica Latham, 1801 | |
The white-necked heron or Pacific heron (Ardea pacifica) is a species of heron that is found on most of the Australian continent wherever freshwater habitats exist. It is also found in parts of Indonesia and New Guinea, but is uncommon in Tasmania. [2] The populations of this species in Australia are known to be nomadic like most water birds in Australia, moving from one water source to another, often entering habitats they have not previously occupied, taking advantage of flooding and heavy rain where the surplus of food allows them to breed and raise their young. Irruptive movements may occur when environmental conditions are right in places where the species has been rare or absent. [3]
The white-necked heron is a large, diurnal, long-legged waterbird. It is mostly slate-grey to black with distinctive black spots in the centre of the lower fore-neck and throat. During the breeding season plum-coloured nuptial plumes are present on the back and breast. [2] The flight is stately, with slow steady wing-beats. [3] Body size/length 76–106 cm, Wingspan 147–160 cm, weight 860g. [2]
The bill is black and the facial skin is commonly blue or yellow. The eyes are green and the legs and feet black. [4] It has an elongated neck and beak designed to reach out and catch fish, frogs, spiders and other food animals available in its habitat. Most of the head and neck is white, with the black spots on the neck only visible in non-breeding individuals. [2]
In the downy young, the down is longer, especially on the crown, with the neck and head white and upperparts and upper wing light grey-brown. Juvenile feathers are dark grey. In juveniles a broad strip of grey-black runs down the front of the neck. The head and neck are commonly tinged brownish-grey. The adult feathers emerge as the juvenile feathers become worn. [2]
The white-necked heron is found throughout most of the Australian continent, commonly residing in wetlands, tidal areas, shallow fresh waters, farm dams, claypans, pastures and runoff water in roadside ditches. [5] The species has thrived following the construction of irrigation, dams and other man-made water sources. [2]
The species is not found in some parts of Western Australia and South Australia, nor in the arid Great Sandy, Gibson, and Great Victoria Deserts or the Nullarbor Plain. Movements are still largely unknown due to irruptive habits, which are commonly attributed to genetic adaptions to erratic environmental conditions. [2]
The white-necked heron is a shy bird, keeping to areas where it has a clear view of its surrounds. [6] Commonly found in shallow wetlands, it is usually seen foraging singly or in pairs. It will defend feeding territories against other species and has been seen harassing ibises ( Threskiornis moluccus ) and raptors, often stealing prey they have caught. When water sources dry up they fly to others at an altitude of 30-100m. Their habitat includes terrestrial wetlands, grasslands and flooded pastures as well as farm dams.
The nest is made from bulky materials (twigs and sticks about 1 cm-2 cm in diameter) very loosely constructed on a platform with a depression in the middle and usually measures 30 cm-60 cm across. [2] Nests are commonly at a height of between 15m-30m above the ground on a tree structure associated with access to a close a food and water source. [7] During breeding seasons males have been observed standing on or near the nest structure for very long periods, fiddling with nesting material, preening, and displaying himself. [2] The male has also been observed displaying a dance of the following movements: starting at a normal stance, the bird brings its body into a horizontal position, throwing its head back nearly reaching the body. Stretching its head skyward and pumping its head three to four times over the course of a minute. With legs bent, exclaiming an "oomph" call or guttural croak. [2]
Breeding frequency is once a year. The bond between males and females of the species is assumed to be monogamous. The nesting season is from September to December and sometimes January. [2] It has suggested eggs are incubated for 30 days before hatching. [8] Eggs are light blue-green, measuring 53mm x 38mm. Clutch sizes usually consist of four eggs but as many as six have been known to occur. Breeding success rate is between 0.3 and 1.8 young to maturity, eggs incubated by both parents. [2] When the chicks hatch, the parents alternate shifts to provide shade with their wings. Their first flights take place at about 6–7 weeks of age. They start leaving the nest when they are 3⁄4 grown. [2]
The diet includes freshwater mussels, fish, shrimp, freshwater crayfish, spiders, dragonfly nymphs, damselflies, praying mantis, grasshoppers, water beetles, lizards, young ducklings, young rodents and amphibians. The young are fed with regurgitated tadpoles and may knock smaller young out of the nest in competition for the food source. [2]
The species is considered to be secure in all states and territories of Australia. [4]
The brolga, formerly known as the native companion, is a bird in the crane family. It has also been given the name Australian crane, a term coined in 1865 by well-known ornithologist John Gould in his Birds of Australia.
The great blue heron is a large wading bird in the heron family Ardeidae, common near the shores of open water and in wetlands over most of North and Central America, as well as far northwestern South America, the Caribbean and the Galápagos Islands. It is occasionally found in the Azores and is a rare vagrant to Europe. An all-white population found in south Florida and the Florida Keys is known as the great white heron. Debate exists about whether this represents a white color morph of the great blue heron, a subspecies of it, or an entirely separate species.
Herons are long-legged, long-necked, freshwater and coastal birds in the family Ardeidae, with 72 recognised species, some of which are referred to as egrets or bitterns rather than herons. Members of the genera Botaurus and Ixobrychus are referred to as bitterns, and, together with the zigzag heron, or zigzag bittern, in the monotypic genus Zebrilus, form a monophyletic group within the Ardeidae. Egrets do not form a biologically distinct group from herons, and tend to be named differently because they are mainly white or have decorative plumes in breeding plumage. Herons, by evolutionary adaptation, have long beaks.
The grey heron is a long-legged wading bird of the heron family, Ardeidae, native throughout temperate Europe and Asia, and also parts of Africa. It is resident in much of its range, but some populations from the more northern parts migrate southwards in autumn. A bird of wetland areas, it can be seen around lakes, rivers, ponds, marshes and on the sea coast. It feeds mostly on aquatic creatures which it catches after standing stationary beside or in the water, or stalking its prey through the shallows.
The purple heron is a wide-ranging heron species. It breeds in Africa, central and southern Europe, and southern and eastern Palearctic. The Western Palearctic populations migrate between breeding and wintering habitats whereas the African and tropical-Asian populations are primarily sedentary, except for occasional dispersive movements.
The great egret (Ardea alba), also known as the common egret, large egret, or great white egret or great white heron is a large, widely distributed egret. The four subspecies are found in Asia, Africa, the Americas, and southern Europe. Recently it is also spreading to more northern areas of Europe. Distributed across most of the tropical and warmer temperate regions of the world, it builds tree nests in colonies close to water.
Forster's tern is a tern in the family Laridae. The genus name Sterna is derived from Old English "stearn", "tern", and forsteri commemorates the naturalist Johann Reinhold Forster.
The Asian woolly-necked stork or Asian woollyneck is a species of large wading bird in the stork family Ciconiidae. It breeds singly, or in small loose colonies. It is distributed in a wide variety of habitats including marshes in forests, agricultural areas, and freshwater wetlands across Asia.
The white-faced heron also known as the white-fronted heron, and incorrectly as the grey heron, or blue crane, is a common bird throughout most of Australasia, including New Guinea, the islands of Torres Strait, Indonesia, New Zealand, and all but the driest areas of Australia.
The black-necked stork is a tall long-necked wading bird in the stork family. It is a resident species across the Indian Subcontinent and Southeast Asia with a disjunct population in Australia. It lives in wetland habitats and near fields of certain crops such as rice and wheat where it forages for a wide range of animal prey. Adult birds of both sexes have a heavy bill and are patterned in white and irridescent blacks, but the sexes differ in the colour of the iris with females sporting yellow irises and males having dark-coloured irises. In Australia, it is known as a jabiru although that name refers to a stork species found in the Americas. It is one of the few storks that are strongly territorial when feeding and breeding.
The little blue heron is a small heron of the genus Egretta. It is a small, darkly colored heron with a two-toned bill. Juveniles are entirely white, bearing resemblance to the snowy egret. During the breeding season, adults develop different coloration on the head, legs, and feet.
The Goliath heron, also known as the giant heron, is a very large wading bird of the heron family, Ardeidae. It is found in sub-Saharan Africa, with smaller, declining numbers in Southwest and South Asia.
The nankeen night heron is a heron that belongs to the genus Nycticorax and the family Ardeidae. Due to its distinctive reddish-brown colour, it is also commonly referred to as the rufous night heron. It is primarily nocturnal and is observed in a broad range of habitats, including forests, meadows, shores, reefs, marshes, grasslands, and swamps. The species is 55 to 65 cm in length, with rich cinnamon upperparts and white underparts. The nankeen night heron has a stable population size, and is classified as a species of least concern by the International Union for Conservation of Nature (IUCN).
The blue-billed duck is a small Australian stiff-tailed duck, with both the male and female growing to a length of 40 cm (16 in). The male has a slate-blue bill which changes to bright-blue during the breeding season, hence the duck's common name. The male has deep chestnut plumage during breeding season, reverting to a dark grey. The female retains black plumage with brown tips all year round. The duck is endemic to Australia's temperate regions, inhabiting natural inland wetlands and also artificial wetlands, such as sewage ponds, in large numbers. It can be difficult to observe due to its cryptic nature during its breeding season through autumn and winter. The male duck exhibits a complex mating ritual. The blue-billed duck is omnivorous, with a preference for small aquatic invertebrates. BirdLife International has classified this species as Least concern. Major threats include drainage of deep permanent wetlands, or their degradation as a result of introduced fish, peripheral cattle grazing, salinization, and lowering of ground water.
Humblot's heron, also known as the Madagascar heron, is a species of heron. It is commonly found on the north and west coasts of Madagascar but it is also present in the Comoro Islands and Mayotte. Humblot's heron is considered an endangered species due to its declining population. The major threats the heron faces are poaching, habitat destruction, and the invasion of alien species such as the water hyacinth.
The white-bellied heron also known as the imperial heron or great white-bellied heron, is a large heron species living in the foothills of the eastern Himalayas in northeast India and Bhutan to northern Myanmar. It inhabits undisturbed rivers and wetlands. It has been listed as Critically Endangered on the IUCN Red List since 2007, because the global population is estimated at less than 300 mature individuals and threatened by habitat loss and human disturbance. It is mostly dark grey with a white throat and underparts.
The cocoi heron is a species of long-legged wading bird in the heron family Ardeidae found across South America. It has predominantly pale grey plumage with a darker grey crest. A carnivore, it hunts fish and crustaceans in shallow water.
The maguari stork is a large species of stork that inhabits seasonal wetlands over much of South America, and is very similar in appearance to the white stork; albeit slightly larger. It is the only species of its genus to occur in the New World and is one of the only three New World stork species, together with the wood stork and the jabiru.
The Sakalava rail is a species of bird in the family Rallidae. It is endemic to western Madagascar. This bird is small with brown upperpart feathers, grey underparts, a yellow bill and red legs.
The Australian pratincole is a species of bird in the family Glareolidae. It breeds in Australia's interior; it winters to northern and eastern parts of the continent, Indonesia and New Guinea. It is a medium-sized nomadic shorebird which is commonly found in arid inland Australia. It breeds predominantly from south-western Queensland to northern Victoria and through central Australia to the Kimberley region in Western Australia. The Australian population is estimated at 60,000 individuals. They are a migratory species that generally move to the southern parts of their distribution range to breed during spring and summer. During winter they migrate to northern Australia, New Guinea, Java, Sulawesi and southern Borneo to over-winter. Although they are common, their occurrence is unpredictable and varies in location.