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Herons are long-legged, long-necked, freshwater and coastal in the family Ardeidae, with 75 recognised species, some of which are referred to as or rather than herons. Members of the genus Botaurus 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 classification of the individual heron/egret species is fraught with difficulty, and no clear consensus exists about the correct placement of many species into either of the two major genera, Ardea and Egretta. Similarly, the relationships of the genus in the family are not completely resolved. However, one species formerly considered to constitute a separate monotypic family, the Cochlearidae or the boat-billed heron, is now regarded as a member of the Ardeidae.
Although herons resemble birds in some other families, such as the , , , and cranes, they differ from these in flying with their necks retracted, not outstretched. They are also one of the bird groups that have powder down. Some members of this group nest Bird colony in trees, while others, notably the bitterns, use . A group of herons has been called a "siege".
Herons are also known as shitepokes , or euphemistically as shikepokes or shypokes. Webster's Dictionary suggests that herons were given this name because of their habit of defecating when flushed. "Shitepoke" and "Shikepoke" entries, Webster's Third International Dictionary of the English Language Unabridged, Philip Babcock Gove, Editor in Chief, G. and C. Mirriam Company, 1971
The 1971 Compact Edition of the Oxford English Dictionary describes the use of shitepoke for the small green heron of North America ( Butorides virescens) as originating in the United States, citing a published example from 1853. The OED also observes that shiterow or shederow are terms used for herons, and also applied as derogatory terms meaning a thin, weakly person. This name for a heron is found in a list of game birds in a royal decree of James VI (1566–1625) of Scotland. The OED speculates that shiterow is a corruption of shiteheron."Shitepoke" and "shiterow" entries, Compact Edition of the Oxford English Dictionary, Oxford University Press, 1971, Library of Congress Catalogue Card Number 76-188038
Another former name was heronshaw or hernshaw, derived from the Old French heronçeau. Corrupted to handsaw, this name appears in Shakespeare's Hamlet. A possible further corruption took place in the Norfolk Broads, where the heron is often referred to as a harnser.
The beak is generally long and harpoon-like. It can vary from extremely narrow, as in the agami heron, to wider as in the grey heron. The most atypical heron bill is owned by the boat-billed heron, which has a broad, thick bill. Herons' bills and other bare parts of the body are usually yellow, black, or brown, although this can vary during the breeding season. The wings are broad and long, exhibiting 10 or 11 (the boat-billed heron has only nine), 15–20 secondaries, and 12 rectrices (10 in the bitterns). The feathers of the herons are soft and the plumage is usually blue, black, brown, grey, or white, and can often be strikingly complex. Amongst the day herons, little sexual dimorphism in plumage is seen (except in the pond herons); however, for the night herons and smaller bitterns, plumage differences between the sexes are the rule. Many species also have different colour morphs. In the Pacific reef heron, both dark and light colour morphs exist, and the percentage of each morph varies geographically; its white morphs only occur in areas with coral beaches.
The herons are a highly mobile family, with most species being at least partially bird migration; for example, the grey heron is mostly sedentary in Britain, but mostly migratory in Scandinavia. Birds are particularly inclined to disperse widely after breeding, but before the annual migration, where the species is colonial, searching out new feeding areas and reducing the pressures on feeding grounds near the colony. The migration typically occurs at night, usually as individuals or in small groups.
The most common hunting technique is for the bird to sit motionless on the edge or stand in shallow water and wait until prey comes within range. Birds may either do this from an upright posture, giving them a wider field of view for seeing prey, or from a crouched position, which is more cryptic and means the bill is closer to the prey when it is located. Having seen prey, the head is moved from side to side so that the heron can calculate the position of the prey in the water and compensate for refraction, and then the bill is used to spear the prey.
In addition to sitting and waiting, herons may feed more actively. They may walk slowly, around or less than 60 paces a minute, snatching prey when it is observed. Other active feeding behaviours include foot stirring and probing, where the feet are used to flush out hidden prey. The wings may be used to frighten prey (or possibly attract it to shade) or to reduce glare; the most extreme example of this is exhibited by the black heron, which forms a full canopy with its wings over its body.
Some species of heron, such as the little egret and grey heron, have been documented using bait to lure prey to within striking distance. Herons may use items already in place, or actively add items to the water to attract fish such as the banded killifish. Items used may be man-made, such as bread; alternatively, in the Amazon Basin have been watched repeatedly dropping seeds, insects, flowers, and leaves into the water to catch fish.
Three species, the black-headed heron, whistling heron, and especially the cattle egret, are less tied to watery environments and may feed far away from water. Cattle egrets improve their foraging success by following large grazing animals, and catching insects flushed by their movement. One study found that the success rate of prey capture increased 3.6 times over solitary foraging.
Courtship usually takes part in the bird nest. Males arrive first and begin the building of the nest, where they display to attract females. During courtship, the male employs a stretch display and uses erectile neck feathers; the neck area may swell. The female risks an aggressive attack if she approaches too soon and may have to wait up to four days.Kushlan, J. A. (2011). The terminology of courtship, nesting, feeding and maintenance in herons . heronconservation.org In colonial species, displays involve visual cues, which can include adopting postures or ritual displays, whereas in solitary species, auditory cues, such as the deep booming of the bitterns, are important. The exception to this is the boat-billed heron, which pairs up away from the nesting site. Having paired, they continue to build the nest in almost all species, although in the little bittern and least bittern, only the male works on the nest.
Some Ornithology have reported observing female herons attaching themselves to impotent mates, then seeking sexual gratification elsewhere.
The nests of herons are usually found near or above water. Although the nests of a few species have been found on the ground where suitable trees or shrubs are unavailable, they are typically placed in vegetation. Trees are used by many species, and here they may be placed high up from the ground, whereas species living in reed beds may nest very close to the ground. Though the majority of nesting of herons is seen in or immediately around water, colonies commonly occur in several cities when human persecution is absent.
Generally, herons lay between three and seven eggs. Larger clutches are reported in the smaller bitterns and more rarely some of the larger day herons, and single-egg clutches are reported for some of the tiger herons. Clutch size varies by latitude within species, with individuals in temperate climates laying more eggs than tropical ones. On the whole, the eggs are glossy blue or white, with the exception being the large bitterns, which lay olive-brown eggs.
The night herons may still warrant separation from the day herons and egrets (as subfamily Nycticoracinae, as it was traditionally done). However, the position of some genera (e.g. Butorides or Syrigma) is unclear at the moment, and molecular studies have so far suffered from studying only a small number of taxa. Especially among the subfamily Ardeinae, the relationships are very inadequately resolved. The arrangement presented here should be considered provisional.
A 2008 study suggests that this family belongs to the Pelecaniformes. In response to these findings, the International Ornithological Congress reclassified Ardeidae and their sister taxa Threskiornithidae under the order Pelecaniformes instead of the previous order of Ciconiiformes.
The cladogram shown below is based on a molecular phylogenetic study of the Ardeidae by Jack Hruska and collaborators published in 2023. For several species these results conflict with the taxonomy published online in July 2023 by Frank Gill, Pamela Rasmussen and David Donsker on behalf of the International Ornithological Committee (IOC). The least bittern ( Ixobrychus exilis) and the stripe-backed bittern ( Ixobrychus involucris) were nested with members of the genus Botaurus. Hruska and collaborators resurrected the genus Calherodius Peters, 1931 to contain two night herons (the white-backed night heron and the white-eared night heron) that were previously placed in Gorsachius. The western cattle egret ( Bubulcus ibis) was embedded in the genus Ardea. The eastern cattle egret ( Bubulcus coromandus) was not sampled. The placement of the forest bittern ( Zonerodius heliosylus) was ambiguous, but the results suggest that it is probably closely related to members of the genus Ardeola rather than to the subfamily Tigriornithinae.
As of August 2024 the IOC lists 75 heron species, divided into 18 genera.
Other prehistoric and fossil species are included in the respective genus accounts. In addition, Proherodius is a disputed fossil which was variously considered a heron or one of the extinct long-legged waterfowl, the Presbyornithidae. It is only known from a sternum; a tarsometatarsus that had been assigned to it actually belongs to the paleognath Lithornis vulturinus.
In some Native American cultures, this bird symbolizes renewal, rejuvenation, and rebirth – an ever-present reminder that we are all a part of a larger cycle of life and death.
Symbolic meaning in mysticism
In Buddhism, a heron symbolizes purity, transformation, and the wisdom of the Buddha. In addition, as a bird that transcends elements – on the earth, in the water, and the air – the heron symbolizes the expansion of awareness and the ubiquity of consciousness.
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